Diagnosing nail-patella syndrome: can it be so simple?

Abstract

We describe here an interesting case of a 7-day-old male infant brought with parental concerns of inability to extend both knees. Clinical evaluation revealed dysplastic fingernails, bilateral abnormal patellae, triangular lunules in conjunction with pathognomic iliac horns on pelvic radiographs suggesting the possibility of nail-patella syndrome (NPS). Other competing diagnoses with similar phenotypic features were considered and sequentially excluded. A definitive diagnosis was established by the identification of the principal mutation at the LMX1B gene locus of chromosome 9. NPS is seldom diagnosed in neonates due to the heterogeneity of clinical presentations as well as the subtlety of clinical clues in this population. NPS is a dominantly inherited disorder that is predominantly familial in origin and thus carries important implications for the prenatal diagnosis of future pregnancies as well as pre-emptive surveillance of nephropathy in the index child.