Transglutaminase 1 gene mutation in a family with lamellar ichthyosis.

Objective To report a consanguineous family with lamellar ichthyosis and to detect the mutations in transglutaminase 1 (TGM1) gene in this family. Methods Genomic DNA was extracted from the blood samples of a 19-year-old male patient with lamellar ichthyosis, his family members and 100 normal human controls. PCR was carried out to amplify all the encoding sequences (15 exons) and adjacent flanking sequences of TGM1 gene followed by bidirectional sequencing. Results A C1666T mutation in the 11th exon in TGM1 gene, which resulted in the substitution of ACA (threonine) by ATA (isoleucine) at codon 529, was detected in the proband, while both his parents carried the C1666T mutation in heterozygous form, and his sister was a C/C homozygote. None of the 100 normal control individuals carried the mutation in TGMlgene. Conclusions The de novo mutation from ACA (threonine) to ATA (isoleucine) at codon 529, may contribute to the development of lamellar ichthyosis. Consanguineous marriage can increase the risk for lamellar ichthyosis by raising the probability of homozygosis of C 1666T mutation in TGM 1 gene. Key words: lchthyosis, lamellar;  Genes, TGM1;  Mutation