Expression studies of two novel in CIS-mutations identified in an intermediate case of Hunter syndrome.
Hunter syndrome (Mucopolysaccharidosis type II) is a rare X-linked recessive lysosomal storage disorder caused by the deficiency of the enzyme iduronate-2-sulfatase (IDS). To date, more than 200 different mutations have been reported in the IDS gene, located on Xq27.3-q28. Here, we report two new mutations (M488I and G489A) identified in hemizygosity in an Italian Hunter patient. Their "in vitro" expression by COS 7 cells was carried out in order to evaluate their functional consequence on enzyme activity as well as their possible cumulative effect on the malfunctioning of the protein. The results obtained enabled us to confirm the G489A mutation as causative. The M488I mutation, however, could not be unequivocally considered as causing disease because of its residual activity. Although a cumulative effect of the two mutations can be excluded "in vitro," we are cautious about drawing a conclusion with regard to the possible role that the two mutations could have played "in vivo" in modulating the phenotype of the patient. Finally, the knowledge of the molecular defect of the patient has enabled us to identify the carriers, providing reliable genetic counselling to the females of the family.
Ricci
Verena
V
Laboratorio Diagnosi Pre-Postnatale Malattie Metaboliche, Istituto G. Gaslini, Largo G.Gaslini, 16147 Genoa, Italy.
Filocamo
Mirella
M
Regis
Stefano
S
Corsolini
Fabio
F
Stroppiano
Marina
M
Di Duca
Marco
M
Gatti
Rosanna
R
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000378:metabolism; D005817:Genetic Counseling; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D007066:Iduronate Sulfatase / Q000235:genetics; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016532:Mucopolysaccharidosis II / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009841:Oligonucleotides / Q000235:genetics; D010641:Phenotype; D010957:Plasmids; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014960:X Chromosome
D018076:DNA, Complementary; D009841:Oligonucleotides; D007066:Iduronate Sulfatase