Here I present: “Infantile Nephronophthisis”, Victor McKusick, Mendelian Inheritance in Man’, 1966. (NPHP2) 嬰兒腎癆。icd10=Q61.5
INTRODUCTION.
Infantile Nephronophthisis is a severe, early-onset form of nephronophthisis. Nephronophthisis (NPHP) is a group of autosomal recessive ciliopathies that cause chronic tubulointerstitial kidney disease. Infantile NPHP is the most severe subtype, typically presenting in the first year of life.
KEY FEATURES.
1. Age of Onset: Symptoms usually begin in infancy (0–1 year). Progression to end-stage kidney disease (ESKD) by age 2–3 is common.
2. Genetics: Most commonly associated with NPHP2 (INVS) mutations. Part of the larger spectrum of ciliopathies (genes involved in primary cilia function).
3. Pathophysiology: Defective primary cilia → disrupted signaling and tubular architecture. Leads to Corticomedullary cysts, Tubular atrophy, Interstitial fibrosis. Unlike older-onset NPHP, kidneys may be enlarged in the infantile nephronophthisis.
4. Clinical Presentation: Renal Manifestations, Polyuria & polydipsia (concentrating defect), Dehydration episodes, Failure to thrive, Metabolic acidosis, Salt wasting, Progressive renal insufficiency.
There is evidence that infantile nephronophthisis type-2 (NPHP2) is caused by mutation in the inversin gene (INVS) encoded on cytogenetic location 9q31.1 and genomic coordinate 9:100,099,243. INVS is part of a complex of ciliary proteins required for renal and cardiovascular development.
