Autosomal recessive dyskeratosis congenita: a case report and TERT gene mutation analysis / 中华皮肤科杂志

ABSTRACT

Objective:To report a case of autosomal recessive dyskeratosis congenita, and to detect mutations in its causative genes.Methods:Peripheral blood samples were collected from the proband and her parents, genomic DNA was extracted, and 100 unrelated healthy individuals served as controls. The Illumina Nextseq500 sequencer was used to detect sequence variations in coding regions of exons of the skin disease-related genes in the proband′s family, and the causative mutation was verified by PCR-Sanger sequencing. The conservation and pathogenicity of gene mutation sites and corresponding protein structure changes were predicted by using bioinformatics softwares Clustalw2.0, PyMOL, PolyPhen-2, SIFT and FATHMM.Results:The proband clinically presented with reticular poikilodermatous patches on the neck and chest, punctate pigmentation on the axilla, atrophy of some toenails, rough skin and oral leukoplakia, accompanied by abnormality in some indicators of routine blood tests and liver function. Genetic testing showed that the proband carried compound heterozygous mutations c.2452G>A (p.Val818Met) and c.2594G>A (p.Arg865His) in the TERT gene, and the c.2452G>A mutation was not included in the Human Gene Mutation Database. The proband′s mother carried a heterozygous mutation c.2452G>A, and no mutation was identified in the TERT gene of her father or 100 healthy controls. Bioinformatics analysis showed that the amino acid positions 818 and 865 of TERT proteins in multiple species were highly conserved and completely conserved respectively, and the corresponding protein structures changed after the above gene mutations. Based on the clinical manifestations, genetic testing, auxiliary examinations, and bioinformatics analysis results, the patient was finally diagnosed with autosomal recessive dyskeratosis congenita.Conclusion:The compound heterozygous mutations c.2594G>A (p.Arg865His) and c.2452G>A (p.Val818Met) in the TERT gene may be responsible for the clinical phenotype of the proband.