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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
  • Clinical manifestations include mental retardation; muscular hypotonia; hyperphagia; obesity; short stature; hypogonadism; strabismus; and hypersomnolence.[icd9data.com]
  • 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]
  • stature (adult), small hands and feet, mild dysmorphology, and behavior problems which can be severe.[curlie.org]
  • Abstract 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]
  • COMMENTS: 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
  • RESULTS: 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
  • Conclusion: Neonatal hypotonia, reduced FM, feeding difficulties and cryptorchidism should immediately suggest PWS, yet late diagnosis continues in some cases.[ncbi.nlm.nih.gov]
  • RESULTS: Fourteen boys and six girls presented with hypotonia, poor responsiveness, feeding difficulty, and infrequent, weak crying.[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]
  • difficulty, mental retardation, growth failure, hypogonadism and severe obesity.[ncbi.nlm.nih.gov]
Infertility
  • Abstract The use of assisted reproductive technologies (ART) has increased gradually in the treatment of infertility worldwide.[ncbi.nlm.nih.gov]
  • Until recently, experts believed that people with PWS were infertile.[nichd.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
  • Abstract 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]
  • Abstract BACKGROUND AND OBJECTIVES: 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
  • METHOD: 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/m 2 /day), both during 1 year.[ncbi.nlm.nih.gov]
  • RESULTS: 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]
  • Prader-Willi syndrome (PWS) is characterized by extreme floppiness at birth, impaired sexual development, short stature, severe over-eating, characteristic physical features and learning disabilities (LD).[ncbi.nlm.nih.gov]
  • The two main genetic causes and other rarer cause of PWS all involving chromosome 15 give rise to a pattern of atypical early development characterised by extreme floppiness and failure to thrive at birth with the subsequent emergence of severe over-eating[ipwso.org]
Failure to Thrive
  • Abstract 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 two main genetic causes and other rarer cause of PWS all involving chromosome 15 give rise to a pattern of atypical early development characterised by extreme floppiness and failure to thrive at birth with the subsequent emergence of severe over-eating[ipwso.org]
  • CONCLUSION: 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]
  • Abstract BACKGROUND: Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder with different nutritional phases from suckling deficit with failure to thrive to early onset of obesity.[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 affected persons often have an insatiable hunger, overeate and steal food. It is a relatively common congenital disorder with an incidence of about 1 in 10.000 live births.[whonamedit.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]
Increased Appetite
  • 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]
  • 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]
  • People with PWS have high ghrelin levels, which are thought to directly contribute to the increased appetite, hyperphagia, and obesity seen in this syndrome.[en.wikipedia.org]
Cyanosis
  • We present a 17 year-old woman, with a previous genetic diagnosis of Prader-Willi syndrome and BMI of 74 Kg/m(2), that was admitted in anasarca, with marked cyanosis, dyspnea and oliguria.[ncbi.nlm.nih.gov]
Reduced Fetal Movement
  • 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]
Cutaneous Manifestation
  • We present a case of a 27-year-old woman with PWS and describe the typical clinical features and cutaneous manifestations of PWS.[ncbi.nlm.nih.gov]
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]
  • (menkes, textbook of child neurology, 5th ed, p229) Congenital neurobehavioral disorder characterized by rounded face, low forehead, almond shaped eyes, squinting, hypogonadism, hypotonia, insatiable appetite leading to obesity, and mental retardation[icd9data.com]
  • […] scoliosis genu valgum pes planus leg length difference medical hypotonic obese intellectually impaired insatiable appetite hypoplastic genitalia Presentation Symptoms failure to thrive in infancy weak cry aggressive behavior abnormal facial features almond-shaped[orthobullets.com]
Strabismus
  • Strabismus was present in 25 (54%) patients: 22 (48%) patients had esotropia and three (7%) had exotropia. Nine patients either received or required strabismus surgery.[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]
  • Clinical manifestations include MENTAL RETARDATION; MUSCULAR HYPOTONIA; HYPERPHAGIA; OBESITY; short stature; HYPOGONADISM; STRABISMUS; and HYPERSOMNOLENCE.[ncbi.nlm.nih.gov]
  • Characteristic facial features, strabismus and scoliosis are often present.[imprinting-disorders.eu]
Esotropia
  • Strabismus was present in 25 (54%) patients: 22 (48%) patients had esotropia and three (7%) had exotropia. Nine patients either received or required strabismus surgery.[ncbi.nlm.nih.gov]
  • […] 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
  • hands and feet, mild dysmorphology, and behavior problems which can be severe.[curlie.org]
  • 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]
  • First described by Prader, Labhardt and Willi in 1956 on the basis of nine children with the tetrad of small stature, mental retardation, obesity and small hands and feet.[whonamedit.com]
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]
  • (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]
  • A newborn with PWS tends to weigh less than normal, has weak muscles (hypotonia), and may find sucking difficult. Between the ages of 2 and 5 years individuals start developing a voracious appetite. Some, however, may start later.[web.archive.org]
Low Forehead
  • (menkes, textbook of child neurology, 5th ed, p229) Congenital neurobehavioral disorder characterized by rounded face, low forehead, almond shaped eyes, squinting, hypogonadism, hypotonia, insatiable appetite leading to obesity, and mental retardation[icd9data.com]
  • (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]
Round Face
  • (menkes, textbook of child neurology, 5th ed, p229) Congenital neurobehavioral disorder characterized by rounded face, low forehead, almond shaped eyes, squinting, hypogonadism, hypotonia, insatiable appetite leading to obesity, and mental retardation[icd9data.com]
  • (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]
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]
  • 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.[icd9data.com]
  • A key feature of Prader-Willi syndrome is a constant sense of hunger that usually begins at about 2 years of age.[mayoclinic.org]
  • 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]
  • 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]
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]
Behavior Problem
  • 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]
  • CONCLUSION: Parent training is a promising intervention for parents of children with behavior's problems.[ncbi.nlm.nih.gov]
  • problems which can be severe.[curlie.org]
  • COMMENTS: 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]
Tantrums
  • RESULTS: 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]
  • BACKGROUND: 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]
  • A behavioral phenotype with temper tantrums, stubbornness, manipulative behavior and obsessive compulsive disorder is common.[imprinting-disorders.eu]
  • 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]
Sleep Disturbance
  • CONCLUSIONS: 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]
Neonatal Hypotonia
  • Abstract 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]
  • Abstract 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[ncbi.nlm.nih.gov]
  • Conclusion: Neonatal hypotonia, reduced FM, feeding difficulties and cryptorchidism should immediately suggest PWS, yet late diagnosis continues in some cases.[ncbi.nlm.nih.gov]
Lethargy
  • Abstract 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]
  • 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]
  • […] 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]
  • – 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
  • Features included cryptorchidism in 94% males, preterm birth (26%), birthweight 28 days: 1-12 months in seven; and 3.75-10.5 years in five.[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. Journal of the Association of Physicians of India 2011.[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]
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]
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]

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