Objective: To determine the mutations pattern of the genes of a collodion baby.
Methods: Collodion baby is a genetic heterogeneous disease caused by mutations of several genes. Since the most common mutations were observed in TGM1 gene, this gene was chosen for mutation screening. The screening was carried out by PCR and direct sequencing. The allele specific primers were designed for a missense mutation and allele-specific (AS) PCR was carried out in 50 normal individuals for population study.
Results: Three novel alterations were detected in TGM1 gene of the proband, a missense mutation c.463C > T (p.Arg155Trp) in exon 3, a nonsense mutation c.578G > A (p.Trp193X) in exon 4, and a single nucleotide deletion (c.694delG) also in exon 4 of TGM1 gene. This infant's father was heterozygote of c.694delG mutation, while his mother carried the two mutations (c.463C > T and c.578G > A) on the same chromosome. The missense mutation was not detected in his father and in any of the control individuals by AS-PCR.
Conclusion: Three novel mutations were identified in TGM1 gene in a Chinese collodion baby. A double mutation (c.463C > T and c.578G > A) located on the maternal allele while the c.694delG deletion on the paternal allele.