Mutations of transglutaminase-1 in Chinese patients with autosomal recessive congenital ichthyosis: a case report with clinical and genetic analysis of Chinese cases reported in literature

BACKGROUND: Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of diseases of keratinization, characterized primarily by abnormal skin scaling over the whole body surface. Recently, ARCI has been designated to include the major forms of lamellar ichthyosis (LI), congenital ichthyosiform erythroderma (CIE) and harlequin ichthyosis. The first two conditions are the most common major clinical subtypes, and both are caused principally by mutations in the transglutaminase 1 gene, TGM1, although other genes may be responsible in some cases. AIM: To identify the genetic mutations underlying LI in a Chinese family with LI, and to review all the known TGM1 mutations in Chinese patients with ARCI. METHODS: The proband had the severe classic LI phenotype, and was a member of a four-generation family with close blood relationships. We sequenced the DNA of the patients and close relatives. We also reviewed 13 Chinese patients with ARCI from 8 reported families, comprising 10 patients with LI, 2 with CIE and 1 with bathing suit ichthyosis. RESULTS: We characterized 14 different TGM1 mutations. Six of these were reported in other ethnic groups initially and later in Chinese patients, while the remaining eight were first described in Chinese patients. Of the latter, five have been reported only in Chinese patients, while the remaining three have also been reported in other ethnic groups. CONCLUSION: This study expands the current spectrum on TGM1 mutation and increases the knowledge of TGM1 mutation characteristics.