KK Chan, IFM Lo, SWW Cherk, STH Fung, L Leung, DKH Chan, TMF Tong, STS Lam, JCS Ho

Abstract

Oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked recessive disorder characterised by congenital cataracts, mental retardation, and renal tubular dysfunction. OCRL is caused by mutations in the OCRL gene, which encodes for an enzyme phosphatidylinositol 4,5-biphosphate 5-phosphatase [PtdIns(4,5)P2-5ase]. Deficiency of this enzyme impairs proper intracellular protein sorting, especially in the organs of high requirement of PtdIns(4,5)P2-5ase, namely eyes, brain and kidneys. Treatment is system-specific and death usually occurs in the second or third decade of life, mainly due to progressive renal failure. Here we describe the clinical and investigation findings of the first reported case of OCRL in Hong Kong, who presented with congenital cataracts, mental retardation, epilepsy and renal tubular acidosis. Mutational analysis identified a novel hemizygous c.2145_c.2146insTT mutation in the OCRL gene of the proband and his mother. Management of this disease is also discussed.