title: A case of galactosialidosis with novel mutations of the protective protein/cathepsin a gene: diagnosis prompted by trophoblast vacuolization on placental examination.
abstract: Galactosialidosis (GS) is a rare autosomal recessive lysosomal storage disease caused by a combined deficiency of lysosomal β-galactosidase and neuraminidase as a result of a genetic defect in the protective protein/cathepsin A gene. We report a case of unsuspected fetal galactosialidosis presenting as severe intrauterine growth restriction and oligohydramnios prenatally and as hyperinsulinemic hypoglycemia in the immediate postnatal period. Placental pathology examination showed striking vacuolations of the villous syncytiotrophoblast, extravillous trophoblast, and villous Hofbauer cells. Electron microscopy revealed numerous membrane-bound electron-lucent lysosomes, mainly within the syncytiotrophoblast. The characteristic histologic and ultrastructural placental findings prompted biochemical and molecular genetic testing for fetal storage disease. Enzyme activity of β-galactosidase was decreased in leukocytes and fibroblasts. Sialic acid content was elevated. Molecular genetic studies revealed 3 variants--c.108, 110delGCT(L37del), c.1045T>A (C349S), and c.1321C>T(R441C)--of the cathepsin A gene, the latter 2 of which have not been previously reported. These findings are consistent with galactosialidosis. We emphasize the importance of following the accepted practice guideline for the examination of the placenta in discovering unsuspected fetal metabolic disorders.
authors: 1 Department of Pathology, Women & Infants Hospital, Providence, RI, USA.
authors: Stefan
authors: S
authors: Kostadinov
authors: Birju A
authors: BA
authors: Shah
authors: Joseph
authors: J
authors: Alroy
authors: Chanika
authors: C
authors: Phornphutkul
mesh_terms: D000328:Adult; D001706:Biopsy; D043402:Cathepsin A / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007231:Infant, Newborn; D016464:Lysosomal Storage Diseases / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics*; D008854:Microscopy, Electron; D009154:Mutation; D010641:Phenotype; D014327:Trophoblasts / Q000648:ultrastructure*; D014617:Vacuoles / Q000648:ultrastructure*
chemical_list: C468629:CTSA protein, human; D043402:Cathepsin A
keywords: galactosialidosis; lysosomal storage disease; placenta; syncytiotrophoblast; vacuolization