Four novel mutations in the β-galactosidase gene identified in infantile type of GM1 gangliosidosis.

OBJECTIVES: The aim of this study is to find out mutations of Turkish GM1 gangliosidosis patients and to make genotype-phenotype correlations.

DESIGN AND METHODS: β-galactosidase activities were measured by using fluorometric substrate. Mutation screening of 16 exons of β-galactosidase gene and mutation detection were done by PCR-SSCP and DNA sequencing, respectively.

RESULTS: Four new mutations, c.188_189insT in exon 2, c.569_570insA in exon 6, p.K142Q in exon 4, p.G190D in exon 6, and one known mutation p.P549L in exon 15, were identified in the β-galactosidase gene in 5 Turkish patients. Mutations in exons 4 and 6 are in the active site and mutation in exon is in the galactose-binding domain of the β-galactosidase gene.

CONCLUSION: This is the first mutational analysis performed in Turkish GM1 gangliosidosis patients and shows the molecular heterogeneity of the disease in Turkish population. All identified mutations result in severe enzyme deficiency and infantile phenotype.