The i phenotype and congenital cataracts among Chinese in Taiwan

Molecular basis of the adult i phenotype and the gene responsible for the expression of the human blood group I antigen

“…Linkage of adult i phenotype and congenital cataracts has been observed in 3 Taiwanese pedigrees. 27 However, the association does not seem to be as pronounced in the white population. [28][29][30] Molecular genetic analysis of the adult i phenotype may provide a means of identifying the blood group I gene, but it also may facilitate progress in uncovering the basis for the association of the adult i phenotype with a frequent occurrence of congenital cataracts in Asians.…”

“…Identification of the 3 families has been reported. 27 Before the current studies, the Ii phenotypes of the members in the 3 families were confirmed by a tube method using anti-I antibody (a gift from Dr Y. Okubo, Red Cross Blood Center, Osaka, Japan). Total RNA and genomic DNA from these persons were prepared from their peripheral blood cells using the QIAamp RNA Blood Mini Kit (Qiagen GmbH, Hilden, Germany) and the QIAamp DNA Blood Mini Kit (Qiagen), respectively.…”

“…However, RNA samples from other A sample from C-5 was unavailable in the current study; however, she had been shown to have common I phenotype previously. 27 The parents were first cousins. Pedigree drawings (upper) and PCR-SSP-RFLP analysis of the family members (lower) of pedigree S (A) and pedigree W (B).…”

“…Samples from S-1 and S-3 were unavailable in the current study to determine their I genotype; however, these persons were previously demonstrated to have I phenotype. 27 PCR-SSP-RFLP analysis: w and m represent the PCR amplifications using the wild-type primer set and mutant primer set, respectively, for distinguishing the I and I i1 alleles (described in "Materials and methods" and "Results"). The 218-bp PCR products were then digested with Bst UI restriction endonuclease for distinguishing the I and I i2 alleles.…”

“…[28][29][30] Molecular genetic analysis of the adult i phenotype may provide a means of identifying the blood group I gene, but it also may facilitate progress in uncovering the basis for the association of the adult i phenotype with a frequent occurrence of congenital cataracts in Asians. Three Taiwanese adult i pedigrees were previously identified 27 ; the 5 members with adult i phenotype all have congenital cataracts, whereas none of the other 17 members with I phenotype do. In this report we describe the findings of molecular genetic studies of these 3 pedigrees, in which the 2 reported I-branching ␤6GlcNAc-T encoding genes, IGnT and C2GnT-M, were targeted.…”