Exome Sequencing of a Pedigree Reveals S339L Mutation in the TLN2 Gene as a Cause of Fifth Finger Camptodactyly

PLoS One. 2016 May 25;11(5):e0155180. doi: 10.1371/journal.pone.0155180. eCollection 2016.

Abstract

Camptodactyly is a digit deformity characterized by permanent flexion contracture of one or both fifth fingers at the proximal interphalangeal joints. Though over 60 distinct types of syndromic camptodactyly have been described, only one disease locus (3q11.2-q13.12) for nonsyndromic camptodactyly has been identified. To identify the genetic defect for camptodactyly in a four-generation Chinese Han family, exome and Sanger sequencings were conducted and a missense variant, c.1016C>T (p.S339L), in the talin 2 gene (TLN2) was identified. The variant co-segregated with disease in the family and was not observed in 12 unaffected family members or 1,000 normal controls, suggesting that p.S339L is a pathogenic mutation. Two asymptomatic carriers in the family indicated incomplete penetrance or more complicated compensated mechanism. Most of p.S339L carriers also have relatively benign cardiac phenotypes. Expression of wild and mutant TLN2 in HEK293 cells suggested the predominant localization in cytoplasm. Our data suggest a potential molecular link between TLN2 and camptodactyly pathogenesis.

MeSH terms

  • Adult
  • Amino Acid Substitution
  • Asian People
  • China
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • Exome*
  • Female
  • Fingers / abnormalities
  • HEK293 Cells
  • Hand Deformities, Congenital* / genetics
  • Hand Deformities, Congenital* / metabolism
  • Hand Deformities, Congenital* / pathology
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Male
  • Middle Aged
  • Mutation, Missense*
  • Pedigree*
  • Protein Transport / genetics
  • Talin* / genetics
  • Talin* / metabolism

Substances

  • TLN2 protein, human
  • Talin

Grants and funding

This work was supported by National Natural Science Foundation of China (81101339, 81001476 and 81441033); Natural Science Foundation of Hunan Province, China (10JJ5029); Construction Fund for Key Subjects of the Third Xiangya Hospital, Central South University, China; and Postgraduates Innovative Pilot Scheme of Hunan Province, China (CX2014B109). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.