Abstract:

Objective Nail-patella syndrome (NPS) is a rare hereditary disease that effects multiple systems and holds great difficulty in the clinical diagnosis. This paper described the clinical features, renal pathology and genotype in a girl with NPS, in order to raise the doctors` vigilance in making the clinical diagnosis of NPS. Methods Pathological data of a 9-year-old girl with proteinuria and admitted in Guangzhou Women and Children’s Medical Center Affiliated to Guangzhou Medical University were retrospectively analyzed. Clinical manifestations, renal biopsy findings and the second-generation whole-exon sequencing data were examined. Results Physical examinations identified development abnormalities, including hypoplasia of thumb nail, abnormal clavicle morphology especially on the right side, and inability to abduct of the left elbow joint. Laboratory abnormalities mainly included decreased serum albumin level (30.4 g/L), increased cholesterol level (6.14 mmol/L), the mass proteinuria (55.6 mg/[kg·24h]), accompanied by glomerular hematuria. Renal pathology showed no obvious damages under light microscope, while much disordered collagen-like structure in the basement membrane was observed under the electron microscope. The second-generation whole-exon sequencing found a missense mutation in the exon 5 of the LMX1B gene (c.755t > CP), where leucine (Leu) at position 252 was altered to proline (Pro). At 3 months of discharge follow-up, the urinary protein fluctuated around+positivity, and the serum albumin and cholesterol returned to normal. Conclusion A detailed physical examination holds great importance for the diagnosis of NPS in children with multi-system abnormality. The gene sequencing and pathological characteristics are necessary to make the diagnosis of NPS and to reduce the misdiagnosis.

Key words: nail-patella syndrome, pathology, gene