Hereditary osteoonychodysplasia

Synonyms: nail-patella syndrome, HOOD

Definition, Clinical Manifestation, X-ray Imaging
Nail-patella Syndrome (hereditary osteo-onychodysplasia).
 * rare autosomal dominant inherited disease (mutation of the LMX1B gene on chromosome 9; role in morphogenesis of the glomerular basement membranes);
 * severe deformities (dystrophic changes) of the nails or their aplasia (most visible on the thumbs);
 * aplasia or hypoplasia of the patella;
 * dysplastic changes of the elbow (cubitus valgus) and knee joint (genua valga) – often leading to dislocation of capitulum radii (and restriction of elbow movement) or dislocation of the patella;
 * outgrowth at iliacs („iliac horns“) + open buckets hipbone with prominent anterior superior iliac spine (image of "elephant's ear");
 * spondylolisthesis, scoliosis;
 * pes equinovaris, congenital flat foot, abnormal iris pigmentation, in 3rd to 4th-decade nephropathy with renal failure can occur (about 1/3 of the patients; preceded by proteinuria and hematuria).

Treatment

 * Symptomatic (correction of leg deformities, then possibly patellar dislocation.)