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Prader-Willi Syndrome

Prader Willi Syndrome

Prader–Willi syndrome is a rare, genetic disorder characterized especially by failure to thrive, short stature, mental retardation, hypotonia, functionally deficient gonads, and obesity.

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Presentation

The presentation of Prader-Willi syndrome depends upon the age of the patient.

In fetal life:

  • Reduced fetal movements and abnormal position
  • Polyhydramnios 
  • Requirement for caesarean section

In neonates and children:

In adults:

Short Stature
  • Prader-Willi syndrome is a genomic imprinting disorder, characterized by obesity, hyperphagia, mental retardation, short stature and hypogonadism. The presenting signs and symptoms depend upon the age at which the patient is seen.[ncbi.nlm.nih.gov]
  • The clinical appearance of PWS includes dysmorphic facial features with almond-shaped eyes, a narrow bifrontal diameter, and a thin upper lip; short stature; central obesity; and small hands and feet.[ncbi.nlm.nih.gov]
  • A man diagnosed with 47, XXY during childhood presents an appearance similar to that of Prader-Willi syndrome with hypogonadism and gynecomastia, developmental delay, and short stature and obesity.[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome (PWS) is characterized by infantile lethargy and hypotonia causing poor feeding and failure to thrive, childhood obesity, short stature, and hypogonadism.[ncbi.nlm.nih.gov]
  • PWS is an imprinting paternally inherited disorder of 15q11-13 characterized by hypotonia in infant age, hyperphagia, varied degrees of mental retardation, behavior problems, hypogonadism, short stature, and other less common findings.[ncbi.nlm.nih.gov]
Weakness
  • Fourteen boys and six girls presented with hypotonia, poor responsiveness, feeding difficulty, and infrequent, weak crying.[ncbi.nlm.nih.gov]
  • Studies cited include findings on general ability (IQ), IQ correlates with family members, strengths and weaknesses in cognitive profiles in genetic subtypes, attainment in literacy and numeracy, language, comprehension, modality preferences, executive[ncbi.nlm.nih.gov]
  • Babies display little interest in feeding, and their ability to suck is weak or absent. They will take longer to attain the ability to walk, talk, sit, and stand. Children will go on to develop symptoms of muscular hypotonia (weak muscle tone).[britannica.com]
  • Babies : High-calorie formula may help an infant stay at a healthy weight if he can't eat well because of weak muscle tone.[webmd.com]
Feeding Difficulties
  • Neonatal hypotonia, reduced FM, feeding difficulties and cryptorchidism should immediately suggest PWS, yet late diagnosis continues in some cases.[ncbi.nlm.nih.gov]
  • Fourteen boys and six girls presented with hypotonia, poor responsiveness, feeding difficulty, and infrequent, weak crying.[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome (PWS) is caused by the absence of paternally contributed genes in chromosome 15, and is characterized by hypotonia, feeding difficulty, mental retardation, growth failure, hypogonadism and severe obesity.[ncbi.nlm.nih.gov]
  • Maternal uniparental disomy (UPD) 15 is one of the molecular causes of Prader-Willi syndrome (PWS), a multisystem disorder which presents with neonatal hypotonia and feeding difficulty.[ncbi.nlm.nih.gov]
  • The proband was a 2-year-old boy who had feeding difficulties, generalized hypotonia, frontal bossing, broad forehead, small hands and feet.[ncbi.nlm.nih.gov]
Infertility
  • The use of assisted reproductive technologies (ART) has increased gradually in the treatment of infertility worldwide.[ncbi.nlm.nih.gov]
  • Puberty is delayed in patients of Prader-Willi syndrome and infertility is common. Testing should be done to check for gene abnormalities before birth so that appropriate measures can be taken beforehand.[symptoma.com]
  • Hypogonadism is present in both males and females, and is seen as genital hypoplasia, incomplete pubertal development; and most individuals are infertile. Short stature, and small hands and feet are common features.[imprinting-disorders.eu]
Poor Feeding
  • Prader-Willi syndrome (PWS) is characterized by infantile lethargy and hypotonia causing poor feeding and failure to thrive, childhood obesity, short stature, and hypogonadism.[ncbi.nlm.nih.gov]
  • Hyperphagia and obesity develop after an initial phase of poor feeding and failure to thrive.[ncbi.nlm.nih.gov]
  • Patients with Prader-Willi syndrome (PWS) display poor feeding and social skills as infants and fewer hypothalamic oxytocin (OXT)-producing neurons were documented in adults.[ncbi.nlm.nih.gov]
  • PWS has been historically known as a two stage syndrome, with the first stage characterized by hypotonia (low muscle tone) and poor feeding in infancy, and the second stage exhibiting hyperphagia (an uncontrollable drive to eat), combined with weight[pwsausa.org]
  • The classic neonatal presentation of PWS is profound hypotonia, abnormal, weak, or absent cry, diminished deep tendon reflexes, poor feeding, below-average weight, and often a history of fetal inactivity.[copeds.com]
Overeating
  • Two-year, randomized, double-blind, placebo-controlled cross-over study in 25 young adults with PWS. Cross-over intervention with placebo and GH (0.67 mg/m2/day), both during 1 year.[ncbi.nlm.nih.gov]
  • Twenty-nine of a total 211 patients, diagnosed with PWS over the study period, were diagnosed as having T2DM (13.7%, mean age 15.9 3.6 years).[ncbi.nlm.nih.gov]
  • Four children had spinal curvature at baseline; two improved, two progressed to a brace and two developed an abnormal curve over the observation period.[ncbi.nlm.nih.gov]
  • Access of child to food should be restricted to prevent bouts of overeating and to keep their weight in check. Muscle activity like sports should be encouraged to overcome hypotonia and motor problems.[symptoma.com]
  • However, identifying relevant patients for tests remains a challenge for most practitioners, as many features of the disorder are nonspecific, and others can be subtle or evolved over time.[ncbi.nlm.nih.gov]
Failure to Thrive
  • The change in AG/UAG ratio possibly drives the switch from failure to thrive to obesity. NCT02529085 .[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome (PWS) is characterized by infantile lethargy and hypotonia causing poor feeding and failure to thrive, childhood obesity, short stature, and hypogonadism.[ncbi.nlm.nih.gov]
  • The patient has hypotonia, failure to thrive, and typical dysmorphic facial features for PWS. The patient also has profound global developmental delay consistent with an expanded, more severe, phenotype.[ncbi.nlm.nih.gov]
  • Hyponatremia should be suspected in children with Prader-Willi syndrome, especially in infants with severe failure to thrive. Further studies are needed to determine the pathophysiology of hyponatremia in this syndrome.[ncbi.nlm.nih.gov]
  • Hyperphagia and obesity develop after an initial phase of poor feeding and failure to thrive.[ncbi.nlm.nih.gov]
Insatiable Hunger
  • Along with insatiable hunger, symptoms of the condition include: mild to moderate intellectual impairment and learning disabilities, behavioral problems, sleep abnormalities, and usually infertility.[medicaldaily.com]
  • "The main characteristics are low muscle tone, developmental delays and an insatiable hunger," DiMuccio said. Siena has experienced the first two. She wasn't able to sit up until she was 1.[turnto10.com]
  • Between 3 and 8 years old, people with PWS begin to develop insatiable hunger. “As he’s (Jude) gotten older, there is more of an awareness of food,” said Fischer.[denver.cbslocal.com]
  • Prader-Willi syndrome (PWS) develops as a result of genetic abnormalities due which the child suffers from late speech development, decrease muscle power, insatiable hunger and overeating bouts, obesity, excessive sleeping, weakness and mental retardation[symptoma.com]
  • It is typically characterized by low muscle tone, short stature (when not treated with growth hormone), incomplete sexual development, cognitive disabilities, behavioral problems, and the hallmark characteristics – chronic feelings of insatiable hunger[pwsausa.org]
Increased Appetite
  • Children with PWS have sweet and loving personalities, but this phase is also characterized by increased appetite, weight control issues, and motor development delays along with some behavior problems and unique medical issues.[pwclassic.com]
  • During this phase, the children do not have an increased appetite or increased interest in food.[pwsausa.org]
  • The increased appetite also means there is an increased risk of choking on food, so carers of a child with Prader-Willi syndrome are advised to learn what to do if someone is choking .[nhs.uk]
  • Increased appetite and decreased muscle tone The most notable symptom of Prader-Willi syndrome, for many, is an unusually large, seemingly insatiable appetite.[scoliosisassociates.com]
Reduced Fetal Movement
  • Reduced fetal movements (FM) were reported in 82.5% patients compared with 4% healthy siblings.[ncbi.nlm.nih.gov]
  • In fetal life: Reduced fetal movements and abnormal position Polyhydramnios Requirement for caesarean section In neonates and children: Feeding difficulties (poor suckling reflex) Delayed developmental motor milestones Delayed onset of speech Thick saliva[symptoma.com]
Blonde Hair
  • Someone with PWS may also be born with distinct facial features including almond-shaped eyes, a narrowing of the head, a thin upper-lip, light skin and hair (50% of people have fair skin, blonde hair and blue eyes, regardless of what their family members[hwns.com.au]
  • Around half of all children with Prader-Willi syndrome will have fair skin, blonde hair and blue eyes, regardless of what their family members look like.Children with Prader-Willi syndrome are delayed in all aspects of development, reaching developmental[betterhealth.vic.gov.au]
  • The child usually has blue eyes and blond hair. They tend to lag behind other children in the transition to solid food.[patient.info]
  • She had blue eyes, fair skin, and blond hair. Hypotonia was still present. At 23 months the clinical picture had not changed appreciably. The girl did not yet walk, but she used a few words.[nejm.org]
Almond-Shaped Eyes
  • The clinical appearance of PWS includes dysmorphic facial features with almond-shaped eyes, a narrow bifrontal diameter, and a thin upper lip; short stature; central obesity; and small hands and feet.[ncbi.nlm.nih.gov]
  • Different from western patients, the 20 Asian patients exhibited at least five of the following typical features: prominent forehead, narrow face, almond-shaped eyes, small mouth, downturned mouth, thin upper lip, and micromandible.[ncbi.nlm.nih.gov]
  • Characteristic facial features (a narrow forehead, almond-shaped eyes, a thin upper lip and down-turned mouth), as well as very small hands and feet, are frequently observed.[orpha.net]
  • Dysmorphic findings in a child with Prader-Willi syndrome include narrowing of the temples, almond-shaped eyes, strabismus, and a thin upper lip. Figure 1.[aafp.org]
Strabismus
  • The patient showed neonatal hypotonia, hyperphagia, obesity, central hypogonadism, hypothyroidism, strabismus. Stature and intellectual development are within the normal range.[ncbi.nlm.nih.gov]
  • Characteristic facial features, strabismus and scoliosis are often present.[imprinting-disorders.eu]
  • Dysmorphic findings in a child with Prader-Willi syndrome include narrowing of the temples, almond-shaped eyes, strabismus, and a thin upper lip. Figure 1.[aafp.org]
  • The child’s eyes may cross (strabismus). A frequent feature generally overlooked is thick saliva at the edges of the mouth. Patients also tend to be relatively insensitive to pain.[britannica.com]
Esotropia
  • […] obsessive-compulsive behavior, stubbornness, rigidity, stealing, and lying Sleep disturbance or sleep apnea Short stature by age 15 years (based on the individual family) Hypopigmentation Hands and feet small for height/age Narrow hands with straight ulnar border Esotropia[arupconsult.com]
  • […] scrotum, and small testes in males; hypoplastic labia minora and clitoris in females; and pubertal deficiency) Infantile central hypotonia Rapid weight gain between 1 and 6 years of age Minor criteria Decreased fetal movement and infantile lethargy Esotropia[aafp.org]
  • Eye abnormalities (esotropia, myopia). Thick, viscous saliva crusting at mouth corners. Speech articulation defects. Skin picking. Other features which may be present, many of them related to problems of the hypothalamus: High pain threshold.[patient.info]
Small Hand
  • The clinical appearance of PWS includes dysmorphic facial features with almond-shaped eyes, a narrow bifrontal diameter, and a thin upper lip; short stature; central obesity; and small hands and feet.[ncbi.nlm.nih.gov]
  • The proband was a 2-year-old boy who had feeding difficulties, generalized hypotonia, frontal bossing, broad forehead, small hands and feet.[ncbi.nlm.nih.gov]
  • Our patient had several typical features of PWS including infantile hypotonia, a poor suck and feeding difficulties, tantrums, skin picking, compulsions, small hands and feet, and food seeking, but not hypopigmentation, a micropenis, cryptorchidism or[ncbi.nlm.nih.gov]
  • Genetic analyses were performed in a male patient with suspected Prader-Willi syndrome who presented with hypogonadism, excessive eating, central obesity, small hands and feet and cognition within the low normal range.[ncbi.nlm.nih.gov]
  • Clinically, our patient met the diagnostic criteria of PWS including infantile hypotonia, a poor suck with feeding difficulties, global developmental delays and later food foraging, childhood obesity, small hands and skin picking.[ncbi.nlm.nih.gov]
Muscle Hypotonia
  • Because of weak muscles (hypotonia), the infant is not able to drink from a bottle and may need special feeding techniques or tube feedings until his/her muscles become stronger.[rarediseases.about.com]
  • (hypotonia) learning difficulties lack of sexual development behavioural problems, such as temper tantrums or stubbornness Read more about symptoms of Prader-Willi syndrome .[nhs.uk]
  • […] in part, plays a role in muscle hypotonia and weakness.[medicalhomeportal.org]
  • There are no reports of immune deficiency in PWS, and the increase in respiratory infection may be related to respiratory muscle hypotonia and thus decreased cough.[nature.com]
Round Face
  • (Menkes, Textbook of Child Neurology, 5th ed, p229) Definition (CSP) congenital neurobehavioral disorder characterized by rounded face, low forehead, almond shaped eyes, squinting, hypogonadism, hypotonia, insatiable appetite leading to obesity, and mental[fpnotebook.com]
  • Albright hereditary osteodystrophy can include excess weight and developmental delays and also includes short stature and short metacarpals (especially 4th and 5th digits) but lacks hypotonia and has different characteristic facial appearance (round face[nature.com]
Low Forehead
  • (Menkes, Textbook of Child Neurology, 5th ed, p229) Definition (CSP) congenital neurobehavioral disorder characterized by rounded face, low forehead, almond shaped eyes, squinting, hypogonadism, hypotonia, insatiable appetite leading to obesity, and mental[fpnotebook.com]
Behavior Problem
  • Behavioral problems were significantly correlated with parental restrictive feeding practices.[ncbi.nlm.nih.gov]
  • GABA levels were significantly lower in the participants with PWS who had clinically significant emotional and behavioral problems relative to typically developing control participants and participants with PWS who did not have emotional and behavioral[ncbi.nlm.nih.gov]
  • These findings support the hypothesis that dysregulation of orexin signaling may contribute to behavioral problems and hyperphagia in PWS.[ncbi.nlm.nih.gov]
  • Parent training is a promising intervention for parents of children with behavior's problems.[ncbi.nlm.nih.gov]
Tantrums
  • Important improvements were achieved and maintained including weight loss, decreased need for supplemental oxygen, greater exercise tolerance, and fewer tantrums.[ncbi.nlm.nih.gov]
  • Our patient had several typical features of PWS including infantile hypotonia, a poor suck and feeding difficulties, tantrums, skin picking, compulsions, small hands and feet, and food seeking, but not hypopigmentation, a micropenis, cryptorchidism or[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome (PWS) is known for hyperphagia with impaired satiety and a specific behavioural phenotype with stubbornness, temper tantrums, manipulative and controlling behaviour and obsessive-compulsive features.[ncbi.nlm.nih.gov]
  • Changes in behaviour may also become evident over time with tantrums, stubbornness and mood swings occurring. Treatment There is no cure for Prader Willi syndrome.[brainfoundation.org.au]
  • A behavioral phenotype with temper tantrums, stubbornness, manipulative behavior and obsessive compulsive disorder is common.[imprinting-disorders.eu]
Neonatal Hypotonia
  • Hyperphagia, intellectual disabilities/behavioral disorders, neonatal hypotonia, and hypogonadism are cardinal features for PWS.[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome (PWS) is characterized by neonatal hypotonia, hyperphagia, childhood obesity at an early age, short stature, varying degrees of mental deficiency, and hypogonadism.[ncbi.nlm.nih.gov]
  • The patient showed neonatal hypotonia, hyperphagia, obesity, central hypogonadism, hypothyroidism, strabismus. Stature and intellectual development are within the normal range.[ncbi.nlm.nih.gov]
  • Maternal uniparental disomy (UPD) 15 is one of the molecular causes of Prader-Willi syndrome (PWS), a multisystem disorder which presents with neonatal hypotonia and feeding difficulty.[ncbi.nlm.nih.gov]
  • Prader-Willi syndrome is an uncommon multisystem genetic disorder caused by defects of chromosome 15 (15qll-ql3), often due to deletions or uniparental disomy The syndrome is characterized by neonatal hypotonia, dysmorphic facial features, short stature[ncbi.nlm.nih.gov]
Sleep Disturbance
  • Long-term modafinil therapy may ameliorate the sleep disturbances of Prader-Willi syndrome and should be the focus of future clinical trials.[ncbi.nlm.nih.gov]
  • Some of the behaviors which are common to both Prader-Willi Syndrome and autism are: delays in language and motor development, learning disabilities, feeding problems in infancy, sleep disturbances, skin picking, temper tantrums, and a high pain threshold[autism.com]
  • The neurobehavioral phenotype in individuals with PWS includes hyperphagia, temper tantrums, aggression, specific repetitive and ritualistic behavior, stealing and lying, skin picking, mood and sleep disturbances.[genedx.com]
  • Other issues may include growth hormone deficiency/short stature, small hands and feet, scoliosis, sleep disturbances with excessive daytime sleepiness, high pain threshold, speech apraxia/dyspraxia, and infertility.[ddslearning.com]
  • Behavioral features in childhood include temper tantrums, high pain threshold, sleep disturbances, and skin picking.[aafp.org]
Lethargy
  • Prader-Willi syndrome (PWS) is characterized by infantile lethargy and hypotonia causing poor feeding and failure to thrive, childhood obesity, short stature, and hypogonadism.[ncbi.nlm.nih.gov]
  • […] abnormal position Polyhydramnios Requirement for caesarean section In neonates and children: Feeding difficulties (poor suckling reflex) Delayed developmental motor milestones Delayed onset of speech Thick saliva Weak cry Excessive sleeping Hypotonia Lethargy[symptoma.com]
  • This can cause: Poor feeding (inability to suck) Decreased movement and lethargy Weak cry Poor reflexes Additionally, 90 to 100 percent of infants with the syndrome have delayed motor development, requiring about twice as long to achieve developmental[everydayhealth.com]
  • – small labia minora and clitoris Males – hypoplastic scrotum and cryptorchidism Incomplete and delayed puberty Infertility Developmental delay (mild to moderate), multiple learning disabilities Minor criteria Decreased fetal movement and infantile lethargy[arupconsult.com]
  • […] hypoplastic scrotum, and small testes in males; hypoplastic labia minora and clitoris in females; and pubertal deficiency) Infantile central hypotonia Rapid weight gain between 1 and 6 years of age Minor criteria Decreased fetal movement and infantile lethargy[aafp.org]
Cryptorchidism
  • Neonatal hypotonia, reduced FM, feeding difficulties and cryptorchidism should immediately suggest PWS, yet late diagnosis continues in some cases.[ncbi.nlm.nih.gov]
  • Here we report a case of Prader-Willi syndrome, who presented at 16 years of age with diabetes mellitus and cryptorchidism.[ncbi.nlm.nih.gov]
  • Our patient had several typical features of PWS including infantile hypotonia, a poor suck and feeding difficulties, tantrums, skin picking, compulsions, small hands and feet, and food seeking, but not hypopigmentation, a micropenis, cryptorchidism or[ncbi.nlm.nih.gov]
  • All 14 boys had a small scrotum, including nine with cryptorchidism. Diagnoses were made with microarray comparative genomic hybridization. All 20 infants required feeding tubes.[ncbi.nlm.nih.gov]
  • […] obesity Hyperphagia Characteristic facial features – narrow bifrontal diameter, almond-shaped palpebral fissures, downturned mouth Hypogonadism manifestations Genital hypoplasia Females – small labia minora and clitoris Males – hypoplastic scrotum and cryptorchidism[arupconsult.com]
Clitoral Hypoplasia
  • History See the list below: Infants with Prader-Willi syndrome (PWS) commonly exhibit hypotonia, poor suck (with requirement of gavage feedings), weak cry, and genital hypoplasia (eg, cryptorchidism , scrotal hypoplasia, clitoral hypoplasia). [37] Neonatal[emedicine.medscape.com]
  • hypoplasia 76%, primary amenorrhea 56%, spontaneous menarche (mostly spotting) 44% of those older than 15 years; in both sexes: premature pubarche 14%, and precocious puberty 3.6% (one male and two females).[nature.com]
Small Scrotum
  • All 14 boys had a small scrotum, including nine with cryptorchidism. Diagnoses were made with microarray comparative genomic hybridization. All 20 infants required feeding tubes.[ncbi.nlm.nih.gov]
Microscopic Hematuria
  • The patient was admitted to our hospital due to proteinuria and microscopic hematuria after an upper respiratory infection. The occurrence of cardiovascular events has been reported as a cause of death in obese PWS patients.[ncbi.nlm.nih.gov]
Hunger
  • Mindfulness-based strategies included mindful eating, visualizing and labeling hunger, and rapidly shifting attention away from hunger by engaging in Meditation on the Soles of the Feet.[ncbi.nlm.nih.gov]
  • Hypothalamic dysfunction underlies most of the symptoms of Prader-Willi syndrome, leading to disturbances of sleep-wake cycles, sexual characteristics, hunger and satiety, pain and temperature sensations.[symptoma.com]
  • It causes poor muscle tone, low levels of sex hormones and a constant feeling of hunger. The part of the brain that controls feelings of fullness or hunger does not work properly in people with PWS. They overeat, leading to obesity .[medlineplus.gov]
  • Additionally, the distinct white matter alterations might explain the symptoms associated with food intake in PWS, including excessive hyperphagia and constant hunger. Hum Brain Mapp 38:4228-4238, 2017. 2017 Wiley Periodicals, Inc.[ncbi.nlm.nih.gov]
  • Hunger was quantified on a visual analogue scale from 0 to 100.[journals.plos.org]
Emotional Outbursts
  • Does Your Child Have Emotional Outbursts? See a Full List of Topics![thedoctorstv.com]
  • Emotional outbursts. Mood changes. Obsessive or compulsive behaviors. Stubbornness. To help manage these behavioral issues, daily routines, firm rules and positive rewards can help.[gillettechildrens.org]

Workup

Diagnosis is established with the help of the following investigations.

  • Prenatal DNA testing for gene abnormalities
  • Southern blotting for DNA methylation patterns
  • Polymerase chain reaction (PCR)
  • Parental DNA sampling for disomy
  • Fluorescent in situ hybridization (FISH)
  • Chorionic villus sampling and amniocentesis
  • Screening tests for serum insulin like growth factor-1 (IGF-1), growth hormone levels and glycosylated hemoglobin
  • Thyroid function tests
  • Magnetic Resonance Imaging (MRI) in case of (hypopituitarism)
  • Serial dual energy x-ray absorptiometry (DEXA) scanning (osteoporosis)
  • X-ray of the chest
  • Abdominal ultrasonography
  • Computerized Tomography (CT) scans

Treatment

There is no cure for Prader-Willi syndrome as it is a gene defect. The treatment is done for the management of acute symptoms of the disease [3]. It consists of the following.

  • Symptomatic management of the following conditions is done to minimize morbidity.
  • Growth hormone therapy helps improve the skeletal and muscle defects of Prader-Willi syndrome, in particular hypotonia [9][10].
  • Vitamin D supplementation in these patients is associated with good results.
  • Surgical management of respiratory difficulties may be indicated if the symptoms are severe. Tracheostomy may need to be done.

Prognosis

The condition is associated with development of secondary disorders like diabetes mellitus which can lead to comorbidities. Gastric and respiratory problems may lead to death. The overall prognosis is poor.

Etiology

The syndrome arises due to deletion of genes on the chromosome 15 in the region 15q11-13 along with gene imprinting in maternal chromosomes [1]. Mutations or translocation of the genes may also give rise to Prader-Willi syndrome.

Epidemiology

Prader-Willi syndrome occurs in about 1 in 10,000 to 1 in 25,000 newborns. The occurrence of this disease is sporadic. It affects male and females equally. No gender, racial or ethnic predisposition has been found.

The syndrome is not heritable as this is an acquired anomaly of the embryonic life. However, rare genetic changes in Prader-Willi syndrome can be passed on. Recurrence of the syndrome in siblings is uncommon.

Sex distribution
Age distribution

Pathophysiology

Deletion of genes on the chromosome 15 in the region 15q11-13 leads to this abnormality. The underlying gene defect can occur by any of the three pathways:

  • Deletion of genes in the paternal chromosomes.
  • Genomic imprinting (and resultant silencing) of corresponding genes in the maternal chromosomal set.
  • Uniparental disomy (UPD) can be another of the mechanisms of gene defects.

These genes usually code for certain small nucleolar RNAs (snoRNAs) which have regulatory as well as other functions.
Loss of SNORD116 gene cluster and OCA2 genes is common in Prader-Willi syndrome. This leads to hypopigmentation of skin and hair that is associated with the disorder.

Hypothalamic dysfunction underlies most of the symptoms of Prader-Willi syndrome, leading to disturbances of sleep-wake cycles, sexual characteristics, hunger and satiety, pain and temperature sensations.

Prevention

The following measures should be adopted in order to minimize the morbidity from Prader-Willi syndrome.

  • Parental genetic counseling should be done.
  • Due to poor muscle power, neonates should be handled and picked up carefully.
  • Strict dietary control should be observed for prevention of obesity. A balanced diet should be followed. All essential nutrients should be made a part of diet. Access of child to food should be restricted to prevent bouts of overeating and to keep their weight in check.
  • Muscle activity like sports should be encouraged to overcome hypotonia and motor problems.
  • Steroid therapy should be avoided as it tends to exacerbate the behavioral dysfunction
  • Monitoring of children should be done to prevent respiratory and gastric difficulties.
  • A strict sleeping routine should be followed to avoid daytime sleepiness and other sleep-related abnormalities.
  • Behavioral problems should be handled with patience. If needed, psychiatric help should be sought.
  • Parental screening tests should be carried out to assess the risk of recurrence of the disease with further pregnancies.

Summary

Prader-Willi syndrome (PWS), also known as Prader-Labhart-Willi syndrome, is a rare genetic disorder that arises due to genetic abnormalities. It is a multiphasic disorder that can lead to obesity in children.

Delayed onset of development is commonly observed in the cases of PWS. Behavioral and cognitive problems are also common in such children along with some degree of intellectual deficit.

Patient Information

Prader-Willi syndrome (PWS) develops as a result of genetic abnormalities due which the child suffers from late speech development, decrease muscle power, insatiable hunger and overeating bouts, obesity, excessive sleeping, weakness and mental retardation. Short stature and short hands and feet are typical of PWS. Growth retardation is common and such children fail to thrive. Puberty is delayed in patients of Prader-Willi syndrome and infertility is common.

Testing should be done to check for gene abnormalities before birth so that appropriate measures can be taken beforehand. The disease is rarely passed onto the next generation and is compatible with life but a lot of abnormalities develop in such patients. Presence of Prader-Willi syndrome in one child does not mean that further pregnancies will result in recurrence of the syndrome.

References

Article

  1. Cassidy SB. Prader-Willi syndrome. Characteristics, management, and etiology. The Alabama journal of medical sciences. Apr 1987;24(2):169-175.
  2. Witkowski R, Ullrich E, Pietsch P, et al. [Infant hypotonia, obesity, hypogenitalism and oligophrenia--new viewpoints on the etiology and symptoms of Prader-Willi syndrome]. Psychiatrie, Neurologie, und medizinische Psychologie. May 1985;37(5):255-261.
  3. Zipf WB. Prader-Willi syndrome: the care and treatment of infants, children, and adults. Advances in pediatrics. 2004;51:409-434.
  4. Altman K, Bondy A, Hirsch G. Behavioral treatment of obesity in patients with Prader-Willi syndrome. Journal of behavioral medicine. Dec 1978;1(4):403-412.
  5. De Peppo F, Di Giorgio G, Germani M, et al. BioEnterics intragastric balloon for treatment of morbid obesity in Prader-Willi syndrome: specific risks and benefits. Obesity surgery. Nov 2008;18(11):1443-1449.
  6. Scheimann A, Butler MG, Stevenson D, Miller JL, Cuffari C, Klish WJ. "Efficacy of laparoscopic sleeve gastrectomy as a stand-alone technique for children with morbid obesity" and "BioEnterics intragastric balloon for treatment of morbid obesity in Prader-Willi syndrome: specific risks and benefits". Obesity surgery. May 2009;19(5):671-672; author reply 673.
  7. Eiholzer U, Grieser J, Schlumpf M, l'Allemand D. Clinical effects of treatment for hypogonadism in male adolescents with Prader-Labhart-Willi syndrome. Hormone research. 2007;68(4):178-184.
  8. Benarroch F, Hirsch HJ, Genstil L, Landau YE, Gross-Tsur V. Prader-Willi syndrome: medical prevention and behavioral challenges. Child and adolescent psychiatric clinics of North America. Jul 2007;16(3):695-708.
  9. Hoybye C, Hilding A, Jacobsson H, Thoren M. Growth hormone treatment improves body composition in adults with Prader-Willi syndrome. Clinical endocrinology. May 2003;58(5):653-661.
  10. Craig ME, Cowell CT, Larsson P, et al. Growth hormone treatment and adverse events in Prader-Willi syndrome: data from KIGS (the Pfizer International Growth Database). Clinical endocrinology. Aug 2006;65(2):178-185.

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Last updated: 2018-06-22 01:14