34722 Nail-patella syndrome: An early dermatologic diagnosis

Presentation: A 3-month-old female presented with congenital onychodystrophy of both upper extremities and unilateral postaxial polydactyly of her left lower extremity. Physical examination was remarkable for dorsal pterygium of both first fingers, triangular lunulae of the 2nd through 5th fingernails, and Type I postaxial polydactyly of 5th digit without evidence of synonychia. Nail-patella syndrome (NPS) was suspected. Course and therapy: At presentation, radiographs did not show evidence of hypoplastic patellae, elbow abnormalities, or iliac horns. Repeat imaging at 7 months of age suggested the presence of bilateral posterior iliac horns. Based on clinical suspicion, molecular genetic testing was sent. A heterozygous pathogenic variant in LMX1B (c.736C>T (p.Arg246*) was found, confirming a diagnosis of NPS. Discussion: NPS is a clinically variable disorder associated with congenital onychodystrophy, skeletal abnormalities including patellar aplasia or hypoplasia, elbow abnormalities, and pathognomonic iliac horns. Early identifications of NPS is important since almost half of affected individuals develop renal abnormalities including proteinuria, hematuria, nephrotic syndrome, that may progress to end-stage renal disease. Patient may also develop primary open-angle glaucoma and ocular hypertension at an early age. The nail changes, including the presence of the triangular lunulae, are among the earliest and most characteristic findings. This case highlights the role of dermatologists in recognizing these early clinical features to facilitate early multidisciplinary care.