NPS is either present at birth or in early childhood. The features of the disease vary from one person to another. 

Nails

Nail changes are observed in most patients and are usually bilateral [5]. The most commonly involved fingernails are on the first, third, and fifth digits. Furthermore, the thumbnail deformity is more prominent than the others. Specifically, the nails are characteristically small, narrow, thin or thick, ridged, split and possibly discolored. Most cases feature a malformed lunula with a characteristic triangle shape. In contrast to fingernails, the toenails are less affected.

Bones

A majority of patients with NPS exhibit bone abnormalities in the patella. Specifically, one or both patellas are either absent, abnormally small, hypoplastic, or shaped incorrectly [8]. Additionally, the patella may be displaced laterally and superiorly. Knee manifestations are seen in 74% of affected patients according to one study [5].

Other lower extremity bones may also have deformities. Hypoplasia of the fibula and femur causes subluxation or partial dislocation of the knee, which contribute to the restriction of movement. Moreover, patients exhibit genu varum, or "bow-leg" of the affected leg(s). This condition may result in complications such as progressive bone degeneration, knee pain, stiffness, and osteoarthritis.

Elbow involvement is also common in patients with NPS [5]. The deformities are seen in the head of the radius and capitellum of the humerus, of which either can be small and hypoplastic. Some also have webbing of the skin at the antecubital region of the elbow. These patients exhibit a limited range of movement in arm extension, pronation, or supination as well as subluxation. 

In affected hipbones, abnormal projections arise from the superior portions of the bilateral iliac horns. In fact, this is pathognomonic of the disease [5] and can be seen on fetal ultrasound [9]. It is can also be observed on X-rays in affected babies and children. Other skeletal features are scapular hypoplasia, scoliosis, and pectus excavatum [5].

Eyes

Glaucoma is a potentially serious clinical manifestation that occurs secondary to fluid blockage. With increasing fluid pressure, patients may experience headaches, blurry vision, and other visual problems. This condition may progress to loss of peripheral vision and blindness. Other eye abnormalities include the hyperpigmentation of the pupillary margin of the eye called Lester’s sign [5]. In addition, cataracts and microcornea could develop.

Kidneys

Nephropathy, which may present in childhood or later stages, is demonstrated in approximately 30% to 40% of patients. This manifestation is attributed to the degeneration of renal tubules and/or glomeruli. Hence, nephrotic and/or glomerular disease develop.

The first clinical signs of nephropathy are hematuria, hypertension, and possibly edema. While kidney disease could be benign, it has the potential to progress to renal failure. In those with nephropathy, they may develop nephrotic syndrome. Some progress to kidney failure but this is less likely to occur before the fourth decade of life.

Other

There are neurologic symptoms in NPS such as numbness, tingling, and burning sensations represented in a glove and stocking pattern. Furthermore, epilepsy has been reported in a small percentage of patients [5]. Vasomotor symptoms due to poor circulation such as Raynaud’s phenomenon may be present. Also, patients can experience gastrointestinal problems such as constipation and irritable bowel syndrome. Often the former is seen in infancy [5]. Finally, dental issues may arise resulting in weak teeth and thin enamel. The overall general appearance of these individuals is depicted by lean body with little muscle. These patients may have curved spines.

• Asymptomatic

  The individual with NPS may remain asymptomatic for a long while despite showing the visual signs of having misshaped nails. [news-medical.net]

  Once proteinuria is present, it may remit spontaneously, remain asymptomatic, or progress to nephrotic syndrome and occasionally to ESRD. Progression to renal failure may appear to occur rapidly or after many years of asymptomatic proteinuria. [checkorphan.org]

  It may remit spontaneously, remain asymptomatic, or progress to nephritic syndrome and occasionally to renal failure. [pediatricsconsultant360.com]

  Asymptomatic proteinuria is the most common renal presentation. Although a substantial number of patients can progress to nephrotic range proteinuria, development of end-stage kidney disease is rare. [indianjnephrol.org]

• Short Stature

  To describe a case of NPS with short stature and hypothyroidism, an association that has not been described in the literature. [ncbi.nlm.nih.gov]

  The association with short stature was exceptional. 1. [hindawi.com]

  In the current clinical examination she displayed short stature, macrocephaly with a very prominent forehead, synophrys and very thick eyebrows, a broad nasal philtrum with a thin upper lip, down-slanting palpebral fissures, anteverted nostrils, hypertelorism [revistanefrologia.com]

  Common features include disproportionate short stature with short limbs, particularly rhizomelic shortening, true megalencephaly with hydrocephalus in a minority, midface hypoplasia, a trident hand configuration, and joint hyperextensibility. [jmg.bmj.com]

• Nail Abnormality

  Case Details Subluxation of the radial head and bilateral patellar hypoplasia Answer Diagnosis: Nail-Patella Syndrome Also termed Hereditary Osteo-onychodysplasia and Fong syndrome Features: Nails: 80-90% of patients have nail abnormalities, with absent [pedsradiology.com]

  All patients had nail abnormalities (100%), the most frequent finding being hyponychia. Triangular lunulae were observed in four patients. [ncbi.nlm.nih.gov]

  Iliac horns are considered pathognomonic, and the presence of hypoplastic or aplastic patellae in conjunction with nail abnormalities is a cardinal feature of diagnosis. [tandfonline.com]

  On further questioning, it was established that a first‐degree relative had nail abnormalities that were similar to the propositus. Fig. 1. Several dystrophic nails in nail‐patella syndrome. Fig. 1. Several dystrophic nails in nail‐patella syndrome. [ndt.oxfordjournals.org]

  Figure 1: (a and c) Dystrophic nails with abnormal ridging and splitting; (b)- flexion and hyperextension abnormalities of interphalangeal joints causing swan-neck deformity; (d) X-ray showing bilateral iliac horns arising from iliac crest; (e) X-ray [indianjnephrol.org]

• Myxedema

  […] myodystrophia fetalis deformans 変形性胎児筋異栄養症 myoglobin ミオグロビン myoglobinuria ミオグロビン尿/ミオグロビン尿症 myokymia ミオキミア/筋波動症 myopathy 筋障害/ミオパチー myopia 近視 myositis 筋炎 myotonia ミオトニー/筋緊張症 myotonic dystrophy 筋緊張性ジストロフィー MD myotubular myopathy ミオチューブラーミオパチー/筋管様ミオパチー myxedema [jpeds.or.jp]

  Syndrome Metachromatic Leukodystrophy N-Acetylglutamate Synthetase Deficiency Necrobiosis Lipoidica Ochronosis Oculocerebrorenal Dystrophy (Lowe Syndrome) Ornithine Transcarbamylase Deficiency Osteoma Cutis Phenylketonuria Porphyria Cutanea Tarda Pretibial Myxedema [dokterairlangga.com]

• Hypertension

  Angiotensin-converting enzyme (ACE) inhibitors for proteinuria and hypertension Sometimes kidney transplantation There is no specific treatment for nail-patella syndrome, but proteinuria and hypertension can be treated with ACE inhibitors. [msdmanuals.com]

  His medical history was remarkable for glaucoma, hypertension, osteoporosis, and chronic kidney disease. [ncbi.nlm.nih.gov]

  As in our patient, many patients develop hypertension. [mdedge.com]

• Bone Disorder

  Moreover, she has skin and bone disorders similar to those found in the Goltz syndrome. We suggest that monosomy for the COL5A1 gene is responsible for these connective tissue disorders. [ncbi.nlm.nih.gov]

  There are many symptoms for this disease like neurological disorders, bone disorders, dental disorders etc. By genetic testing, nail patella syndrome can be identified and there are number of treatments for the particular disease. [skin-diseases-and-skin-care.imedpub.com]

• Hypoplastic Nails

  Clinically, the key feature is absent/hypoplastic nails from birth. Individuals may have flexion contractures and recurrent knee dislocations. [radiopaedia.org]

  The most common clinical findings are a hypoplastic patella, elbow dysplasia, iliac horns, and hypoplastic nails. Because renal and ophthalmologic complications are prevalent, the management of NPS is multidisciplinary. [insights.ovid.com]

  Nail-patella syndrome characterized by thumbnail hypoplasia (A) as well as triangular lunulae and longitudinal ridging with nail splitting (B). Hypoplastic crumbly toenails were appreciated (C). Figure 2. [mdedge.com]

• Nail Deformity

  Nail deformities are recognized at birth and do not progress: nails are hypoplastic, discolored, and have poorly formed lunulae and/or splitting, most commonly of the thumbnail. [accessanesthesiology.mhmedical.com]

  Nail Patella Syndrome can usually be diagnosed with the naked eye, because there are obvious bone structure and nail deformalities. Pelvic bone mutations found in 80% of Nail Patella patients are not associated with any other disease. [torresbioclan.pbworks.com]

• Skin Disease

  In addition, some affected individuals may have abnormal webbing of skin at the bend of the elbow(s) (antecubital pterygium). [rarediseases.org]

• Hyperactivity

  […] upper arms and upper legs thin bones (osteoporosis) – notably in the hips hairline – the hairline may be high, particularly at the temples It has also been suggested that people with nail patella syndrome may be more likely to have attention deficit hyperactivity [nhsdirect.wales.nhs.uk]

  Hypothyroidism, irritable bowel syndrome, attention deficit hyperactivity disorder (ADHD), and thin tooth enamel are associated with NPS, but whether these are related or simply coincidences are unclear. [4] Genetics [ edit ] The Nail–patella syndrome [en.wikipedia.org]

• Hematuria

  Renal involvement occurs in 30-60% of patients and presents with proteinuria and/or microscopic hematuria, edema, hypertension. [ncbi.nlm.nih.gov]

  Proteinuria, hypertension, and hematuria are the most common manifestations, but about 30% of patients with renal involvement slowly progress to renal failure. [msdmanuals.com]

  Since 1946, several investigators have commented upon the associated finding of proteinuria and hematuria in this syndrome suggesting glomerular involvement.1-8 The renal pathology in this disorder has not been fully delineated, nor have ultrastructural [jamanetwork.com]

• Kidney Failure

  Development of symptomatic kidney failure is rare in this group, and proteinuria (present in approximately one-third) does not appear to be progressive. [ncbi.nlm.nih.gov]

  About half of patients with NPS may have problems with their kidneys ranging from proteinuria (passing protein in the urine), to nephrotic syndrome (proteinuria and swelling), to kidney failure in about 3 per cent of people. [contact.org.uk]

  The kidneys are often affected by the condition. Kidney failure is a concern among patients with this condition, and an early diagnosis is important to prolong the use of the kidneys. Early symptoms of kidney failure include blood in the urine. [brighthub.com]

  Kidney failure eventually develops in about 30% of the people with affected kidneys by the time they are 50 or 60. People who have kidney problems often have high blood pressure (hypertension). [msdmanuals.com]

• Renal Insufficiency

  Blood work revealed a creatine kinase of 389 U/L (normal, <175 U/L), renal insufficiency, anemia, and reduced calcium, phosphorus, and magnesium. Electrocardiogram showed complete heart block with an escape rhythm of 30/min. [ncbi.nlm.nih.gov]

  Pharmacology: impact of renal insufficiency or failure if present, avoid NSAID's. References : Hennessey TA, Backman SB, Meterissian SH, Schriker T. Nail-patella syndrome: a case report and anesthetic implications. Can J Anaesth 2007; 54: 835-9. [sites.uclouvain.be]

  insufficiency Vasculitis (Source: Nail-Patella Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.) [dovemed.com]

  Of these patients, 10% die of renal insufficiency. Both sexes are equally affected. The Cause of Nail Patella Syndrome Nail-patella syndrome has been recognized as an inherited disorder for over a hundred years. [steadyhealth.com]

  insufficiency. • ACE inhibitors are used to treat proteinuria and hypertension. [skin-diseases-and-skin-care.imedpub.com]

The workup includes a thorough physical exam, detailed patient and family history, imaging, and laboratory testing [8]. Fetal ultrasound can detect NPS prenatally with findings suggestive of characteristic limb abnormalities.

Imaging modalities can be utilized. Radiographs, CT, and/or MRI are used to identify bone abnormalities characteristic of NPS such as those found in the patella, radial head or ilium.

Laboratory studies include urinalysis which reveals hematuria and proteinuria. Serum albumin measurement is important in nephrotic patients, in which hypoalbuminemia is demonstrated. Additionally, a complete blood count will detect anemia if present. A combination of anemia, edema, and hypoalbuminemia is highly suspicious of nephrotic syndrome. 

A renal biopsy will display structural abnormalities that may be present even in asymptomatic patients [10]. Histologically, the findings include capillary wall thickening, collagen deposition, and focal and segmental sclerosis.

• Abnormal Renal Function

  Blood pressure and kidney function must be screened annually. For those with abnormal renal function, he/she must be followed more closely by the nephrologist to determine when/if treatment is indicated. [rarediseases.org]

Treatment of NPS consists of symptomatic and supportive measures. Patients with nephropathy are treated with ACE inhibitors for proteinuria. Also, a nephrology consult is indicated in these cases. Patients with open-angle glaucoma are treated the same as the general population. 

In some cases, physical therapy and other early orthopedic interventions are indicated such as knee replacement surgery and/or knee reconstruction. Also, elbow reconstruction surgery may be appropriate. Moreover, management of scoliosis may involve braces, casts or surgery.

Genetic counseling is beneficial in providing information and education for the patient and family members. Genetic screening may be offered, too. Clinicians should consider examination of family members.

NPS patients should undergo surveillance tests to monitor the progression of the disease. Yearly exams include [5]:

• Blood pressure screening
• Screening for renal dysfunction through urinalysis, urine protein/creatinine ratio, and albumin/creatinine ratio
• Screening for presence of glaucoma, cataracts, and microcornea through optic exam

Further management includes monitoring scoliosis in children and adolescents. Caution with NSAIDS, longterm use may have damaging renal effects.

Patients with NPS generally lead ordinary lives but will need close monitoring and surveillance. Those with nephropathy that progresses to end-stage renal disease may require a transplant. Consequently, they do well afterwards.

The etiology of NPS is due to mutations in LMX1B gene, which is a homeobox transcription factor that plays a significant role in the development of limbs, kidneys, and eyes. Specifically, this gene controls the dorsal-ventral pattern of embryological development [3] [4]. Approximately 80% of those with NPS inherited it from an affected parent. One study showed that 87.5% of NPS patients inherited the disorder while the remainder were sporadic. [5]. 

The incidence of NPS is 22 per 1,000,000 population [6]. There is no gender preference in NPS. Abnormalities of nails, knees, and elbows are usually found at birth. However, patellar deformities are noted in childhood while renal manifestations can develop at any age. Also, glaucoma usually develops in adulthood.

NPS occurs as a result of a mutated transcription factor. Various bones are affected such as the patella, ilium, radius, and humerus. Additionally, the nails are affected. Severe features include nephropathy and glaucoma [7]. Approximately 30% to 55% develop nephropathy [5] and about 5% of those with nephropathy progress to end-stage renal failure. It is thought that pathogenic variants of the LMX1B genes may be linked to proteinuria. 

This disease cannot be avoided since it is genetic. However, renal problems and eye abnormalities such as glaucoma could be prevented with close surveillance. Hence, it is paramount for the patient to maintain close follow up with the medical team. Individuals with NPS and their family members may undergo genetic counseling and testing to learn about their chances of inheriting the disease and what NPS entails for future offspring.

Nail-Patella Syndrome (NPS), an autosomal dominant disorder, is characterized by a gene mutation in the transcription factor LMX1B, which results in deformity of nails and bones. Specifically, NPS affects bones in the knees, hips, and elbows. While some presentations are mild and benign, the sequelae vary from one individual to another [1] [2]. Complications include nephropathy and glaucoma.

Diagnosis is achieved through a comprehensive history and physical. Furthermore, it is pertinent to test for any renal or ocular disease through appropriate studies. Early identification of abnormalities results in more prompt treatment and delay of progression. Therefore, surveillance such as annual blood pressure measurement and studies assessing for proteinuria are highly recommended.

Therapy depends on the clinical picture. For individuals with bone deformities, physical therapy and surgical interventions may be indicated. Also, patients with nephropathy or glaucoma will be treated with appropriate medications. Most people commonly lead normal lives but should adhere to close follow up appointments with the medical team.

Nail-Patella Syndrome (NPS) is a disorder due to a mutated gene called LMX1B, which is involved in developing the limbs. NPS is an autosomally dominant disease. This means that one of the parents has a copy of the mutated gene and copy of the good gene. Therefore, there is a 50% chance of passing it to a child. 

This disease affects nails, bones and may even cause problems with kidneys and eyes. Usually, the presentation is at birth. Other cases present in childhood or later. Some individuals will have mild symptoms and signs while others may have more serious ones. The features are:

Nails

• Nails are usually small, ridged, split, thickened, discolored or may be completely absent. 
• Abnormal nails are most commonly found on the thumbs, index, and middle fingers. 

Bones

• One or both patellas (kneecaps) may be abnormal, they could be too small or irregularly shaped.
• Patella may be dislocated and deformed or even absent in one or both legs. The legs may even be bow legged.
• There is knee pain, instability, and possibly limited movement.
• In affected elbows, there is the inability to extend the arm and the elbow may angle outwards.

Kidney                                                      

• Some patients will have protein in their urine without any clinical symptoms. In a small percentage of patients, this may progress to serious problems such as kidney failure although it is rare. 

Eye

• Some patients have glaucoma, which is increased pressure in the eye. Cataracts and other abnormalities may also occur.

Neurological

• Numbness and tingling in hands and feet may be present.

Gastrointestinal

• Commonly found symptoms are irritable bowel syndrome (IBS) or constipation.

Circulation

• Some patiemts will feel cold hand and feet due to inadequate blood supply.

Diagnosis depends on a thorough medical history of the patient and the patient’s family members as well as a detailed exam of the patient. Certain signs of NPS such as hip bone abnormalities can be seen on prenatal ultrasound. Also, X-rays or other imaging can detect abnormalities.

Early intervention to provide support and physical therapy is also impotant. In addition, the patient will have regular follow up appointments. The doctor will monitor blood pressure and perform urine tests to check for protein. Children and adolescents are checked for scoliosis. Also recommended are dental exams twice a year and eye exams to check for glaucoma, cataracts, and other eye problems. Treatment is reserved for signs and symptoms. 

Genetic counseling for the affected individual and family is available and usually beneficial. This involves assessment and discussion of passing on the disorder to future offspring. Parents can make informed decisions under the guidance of a medical professional. Genetic testing may be offered as well. Overall patients live normal lives, but close follow up is the key. 

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2. Turner JW. An hereditary arthrodysplasia associated with hereditary dystrophy of the nails. Journal of American Medical Association. 1933;100(12):882–4.
3. Chen H, Lun Y, Ovchinnikov D, et al. Limb and kidney defects in Lmx1b mutant mice suggest an involvement of LMX1B in human nail patella syndrome. Nature Genetics. 1998; 19(1):51–5.
4. Vollrath D, Jaramillo-Babb VL, Clough MV, et al. Loss-of-function mutations in the LIM-homeodomain gene, LMX1B, in nail-patella syndrome. Human Molecular Genetics. 1998; 7(7):1091.
5. Sweeney E, Fryer A. Nail patella syndrome: a review of the phenotype aided by developmental biology. Journal of Medical Genetics. 2003; 40(3):153–162.
6. Looij BJ Jr, te Slaa RL, Hogewind BL, et al. Genetic counselling in hereditary osteo-onychodysplasia (HOOD, nail-patella syndrome) with nephropathy. Journal of Medical Genetics. 1988; 25(10):682.
7. Lichter PR, Richards JE, Downs CA, et al. Cosegregation of open-angle glaucoma and the nail-patella syndrome. American Journal of Ophthalmology. 1997;124(4):506–15.
8. Bennett WM, Musgrave JE, Campbell RA, et al. The nephropathy of the nail-patella syndrome. Clinicopathologic analysis of 11 kindred. American Journal of Medicine. 1973; 54(3):304.
9. Feingold M, Itzchak Y, Goodman RM. Ultrasound prenatal diagnosis of the nail-patella syndrome. Prenatal Diagnosis. 1998; 18(3):854–6.
10. Chan PC, Chan KW, Cheng IK, et al. Living-related renal transplantation in a patient with nail-patella syndrome. Nephron. 1988; 50(2):164–6.