Nail-Patella Synorome
Helen Liapis, MD
Joseph Gaut, MD, PhD
Key Facts
Etiology/Pathogenesis
LMX1B mutations
Clinical Issues
Iliac horns are pathognomonic (70% of cases)
Absent, hypoplastic, or dystrophic nails
Small, irregularly shaped, or absent patellae
Proteinuria
10% progress to ESRD
Ancillary Tests
Routine transmission electron microscopy sections stained with uranyl acetate show “moth-eaten” GBM
Sequencing LMX1B gene
Top Differential Diagnoses
Collagenofibrotic glomerulopathy
Fibronectin glomerulopathy
Fibrillary glomerulopathy
Hereditary multiple exostoses
 In nail-patella syndrome (NPS), glomeruli typically have minimal changes by light microscopy. The glomerulus illustrated has minimal mesangial hypercellularity. |
 In NPS, phosphotungstic acid stain reveals electron-dense bundles of collagen fibrils  in the GBM by electron microscopy. This stain helps visualize bundles and their ˜ 60 nm periodicity  . |
TERMINOLOGY
Abbreviations
Nail-patella syndrome (NPS)
Synonyms
Hereditary onychoosteodysplasia (HOOD) syndrome
Definitions
Inherited syndrome presenting with nail, skeletal abnormalities, and proteinuria secondary to mutations in LMX1B gene
ETIOLOGY/PATHOGENESIS
