Clinical feature: 

Definition: Nail-patella syndrome is an autosomal dominant disorder. Dysplasia of the nails and absent or hypoplastic patellae are the leading symptoms, occasionally associated with other skeletal abnormalities and hereditary nephritis.

Pathogenesis: Onychoosteodysplasia is caused by mutations of the LMX1B gene.

Epidemiology: The incidence is about 1 in 50,000 live births. The mutation rate seems to correlate with father's age.

Clinical picture: Skeletal abnormalities are striking in onychoosteodysplasia. Patients present with patellar aplasia or hypoplasia, dysplasia of the elbows, iliac horns, and dysplasia of the nails, predominantly the thumb. The disease is often associated with nephropathy and early onset glaucoma.
   In patients suffering from nail-patella syndrome physical and mental performance is not impaired. Life expectation is normal.

Diagnostics: 

Diagnosis: The diagnosis is made by the skeletal abnormalities. Molecular genetic analysis may help to define the underlying mutation and hence elucidation the pathogenesis.

Literature: 

Dreyer SD et al. (1998) Mutations in LMX1B cause abnormal skeletal patterning and renal dysplasia in nail patella syndrome.
Vollrath D et al. (1998) Loss-of-function mutations in the LIM-homeodomain gene, LMX1B, in nail-patella syndrome.
McIntosh I et al. (1998) Mutation analysis of LMX1B gene in nail-patella syndrome patients.
Morello R et al. (2001) Regulation of glomerular basement membrane collagen expression by LMX1B contributes to renal disease in nail patella syndrome.
Marini M et al. (2005) Interaction of the LMX1B and PAX2 gene products suggests possible molecular basis of differential phenotypes in Nail-Patella syndrome.
Hamlington JD et al. (2000) Deletion of a branch-point consensus sequence in the LMX1B gene causes exon skipping in a family with nail patella syndrome.
Dunston JA et al. (2004) The human LMX1B gene: transcription unit, promoter, and pathogenic mutations.
Bongers EM et al. (2005) Genotype-phenotype studies in nail-patella syndrome show that LMX1B mutation location is involved in the risk of developing nephropathy.