OBJECTIVE: To investigate the clinical characteristics and genetic etiology of eight members from a pedigree affected with epidermolysis bullosa (EB). METHODS: A girl presented with recurrent, unexplained blisters on the palmar and plantar skin for 8 years and sought medical care in October 2024 was enrolled as the study subject. A retrospective study was conducted to collect the child's clinical data, and a detailed medical history was taken for her family members. Peripheral venous blood samples were collected from the child and her parents for genomic DNA extraction. Whole-exome sequencing (WES) was performed. Candidate variant was validated by Sanger sequencing. The pathogenicity of the candidate variants was classified in accordance with the Standards and Guidelines for the Interpretation of Sequence Variants issued by the American College of Medical Genetics and Genomics (ACMG, hereinafter referred to as the "ACMG Guidelines"). This study was approved by the Medical Ethics Committee of the 980th Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army (Ethics No.: 2019-KY-01). RESULTS: The proband was an 8-year-and-4-month-old female. Four months after birth, she had developed recurrent blisters on the palmar and plantar skin without obvious triggers, accompanied by significant pain. Symptoms were more severe in summer and slightly relieved in winter. Although symptomatic treatment could alleviate the symptoms, she was unable to participate in physical activities. A detailed family history revealed that her great-grandfather, grandfather, father, half-brother, great-aunt, great-aunt's son and two grandsons, as well as her aunt and aunt's son, had similar clinical manifestations. WES revealed that she has harbored a heterozygous c.556-16(IVS1)C>G (NM_000424.4) variant in the KRT5 gene, which was identified as a splice site mutation. Reverse transcription sequencing confirmed that this variant can disrupt normal splicing, resulting in retention of a 15 bp sequence in the first intron. Sanger sequencing demonstrated that the variant was inherited from the father, and the 6 aforementioned relatives with similar phenotypes have all carried the same variant (the great-grandfather, grandfather, and great-aunt had declined genetic testing due to advanced age). Based on the ACMG guidelines, this variant was classified as pathogenic (PS3+PM2_Supporting+PP3+PP1_strong). CONCLUSION Patients with epidermolysis bullosa simplex may exhibit clinical features including blistering on the skin or mucous membranes of friction-prone sites (e.g. hands, feet, elbows, and knees) following minor trauma or friction, as well as increased skin fragility. The c.556-16(IVS1)C>G (rs376462752) variant of the KRT5 gene probably underlay the pathogenesis of EB in this child. Above findings have enriched the mutational spectrum of the KRT5 gene.
Child ; Female ; Humans ; Infant ; Male ; China ; Epidermolysis Bullosa Simplex/genetics* ; Exome Sequencing ; Keratin-5/genetics* ; Mutation ; Pedigree ; Retrospective Studies ; East Asian People/genetics*

OBJECTIVETo determine the molecular etiology for a Chinese pedigree affected with epidermolysis bullosa simplex (EBS).

METHODSTarget region sequencing using a hereditary epidermolysis bullosa capture array combined with Sanger sequencing and bioinformatics analysis were used. Mutation taster, PolyPhen-2, Provean, and SIFT software and NCBI online were employed to assess the pathogenicity and conservation of detected mutations. One hundred healthy unrelated individuals were used as controls.

RESULTSTarget region sequencing showed that the proband has carried a unreported heterozygous c.1234A>G (p.Ile412Val) mutation of the KRT14 gene, which was confirmed by Sanger sequencing in other 8 affected individuals but not among healthy members of the pedigree. Bioinformatics analysis indicated that the mutation is highly pathogenic. Remarkably, 3 members of the family (2 affected and 1 unaffected) have carried a heterozygous c.1237G>A (p.Ala413Thr) mutation of the KRT14 gene, which was collected in Human Gene Mutation Database (HGMD). Bioinformatics analysis indicated that the mutation may not be pathogenic. Both mutations were not detected among the 100 healthy controls.

CONCLUSIONThe novel c.1234A>G(p.Ile412Val) mutation of the KRT14 gene is probably responsible for the disease, while c.1237G>A (p.Ala413Thr) mutation of KRT14 gene may be a polymorphism. Compared with Sanger sequencing, target region capture sequencing is more efficient and can significantly reduce the cost of genetic testing for EBS.

Adult ; Amino Acid Sequence ; Case-Control Studies ; Epidermolysis Bullosa Simplex ; genetics ; Female ; Humans ; Keratin-14 ; genetics ; Male ; Mutation ; genetics ; Pedigree ; Young Adult

OBJECTIVETo identify keratin 5 (K5) and keratin 14 (K14) gene mutations in a family affected with epidermolysis bullosa simplex with mottled pigmentation.

METHODSGenomic DNA was extracted from peripheral blood samples obtained from eleven patients from the family and controls. All the exons of K5 and K14 genes were amplified using polymerase chain reaction (PCR) and directly sequenced.

RESULTSBy DNA sequence analysis, a missense mutation in K5 gene (c.237C>T) was detected. The same mutation was not found in non-affected members from the family and normal controls.

CONCLUSIONMutation in K5 gene (c.237C>T) may be responsible for the development of disease in this family.

Base Sequence ; DNA Mutational Analysis ; Epidermolysis Bullosa Simplex ; genetics ; pathology ; Exons ; Female ; Humans ; Hyperpigmentation ; genetics ; pathology ; Keratin-14 ; genetics ; Keratin-5 ; genetics ; Male ; Mutation ; Pedigree ; Sequence Analysis, DNA