A case of galactosialidosis with a homozygous Q49R point mutation

Galactosialidosis is a rare lysosomal storage disease caused by a combined deficiency of lysosomal β-galactosidase and neuraminidase, due to a primary defect in protective protein/cathepsin A. Three subtypes are recognized: the early infantile type, the late infantile type, and the juvenile/adult type. Here, we report a case of early infantile galactosialidosis in a female who was born at 31 weeks of gestation, after detection of fetal ascites at 21 weeks of gestation and development of fetal hydrops. After birth she received intensive treatment that led to improvement of edema and pleural effusion, but ascites slowly developed. She died of renal failure on day 207. An autopsy showed that all organs contained vacuolated cells, compatible with a storage disease. The patient had decreased activity of β-galactosidase and undetectable neuraminidase activity in fibroblasts. A single A–G base transition at position 146 of exon 1 (Q49R) in protective protein/cathepsin A gene was found. The mutation has been reported previously in a Japanese patient with different phenotypes. However homozygous Q49R mutation detected in our case was severe prognosis.