Laboratory Medicine ›› 2026, Vol. 41 ›› Issue (2): 133-143.DOI: 10.3969/j.issn.1673-8640.2026.02.006

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Analysis of 3 families with X-linked spondyloepiphyseal dysplasia tarda caused by TRAPPC2 gene variation

WANG Yaqiong1, YING Lingwen2, CHEN Yao2, YAO Ruen3, LOU Dan1, LU Yaya1, LI Juan2, WANG Xiumin2()   

  1. 1. Department of Child Healthcarethe First Affiliated Hospital of Henan University of Science and TechnologyLuoyang 471000,Henan, China
    2. Department of EndocrinologyGenetics and Metabolism,Shanghai Children's Medical Center,Shanghai Jiao Tong University School of MedicineShanghai 200127, China
    3. Department of Genetic and Molecular DiagnosisShanghai Children's Medical Center,Shanghai Jiao Tong University School of MedicineShanghai 200127, China
  • Received:2025-03-03 Revised:2025-12-29 Online:2026-02-28 Published:2026-03-06

Abstract:

Objective To investigate the clinical phenotype and genetic characteristics of X-linked spondyloepiphyseal dysplasia tarda(SEDT) families caused by trafficking protein particle complex subunit 2(TRAPPC2) gene variations. Methods Totall,3 families with X-linked SEDT were enrolled from Shanghai Children's Medical Center of Shanghai Jiao Tong University School of Medicine from January 2019 to September 2024. The clinical data of family members were collected,and whole-exome sequencing(WES) was performed,and bioinformatics analysis was conducted. Suspected mutations were verified by Sanger sequencing. The variations were rated according to the relevant guidelines of American College of Medical Genetics and Genomics(ACMG). Results The probands of all the 3 families were male,and they presented with growth retardation. X-ray of the spine showed flattened vertebrae,depression of the anterior upper and lower margins of the vertebrae,and hump-like protrusions in the middle and posterior parts. The probands of family 1 and family 2 had hemizygous variations c.271_275del(p.Gln91Argfs*9) in TRAPPC2 gene(NM_001011658.4),which were pathogenic variations. The mothers of the probands in these 2 families had heterozygous mutations at this site,while the fathers did not detect the mutation. The proband of family 3 had a hemizygous variation c.191_192delTG(p.Val64Glyfs*24) in the TRAPPC2 gene(NM_001011658.4),and no mutations were found at this site in the parents,and it was considered as a putative de novo variation. Recombinant human growth hormone(rhGH) treatment was used,but the efficacy was poor. Conclusions The SEDT caused by TRAPPC2 gene variations is late-onset and progressive,resulting in disproportionate short stature and premature degeneration of joints. For children with onset in adolescence,if there are abnormal upper and lower body measurements or mismatch in the interphalangeal distance,SEDT should be vigilant. WES is helpful for clarifying the cause.

Key words: Trafficking protein particle complex subunit 2 gene, Deletion mutation, X-linked spondyloepiphyseal dysplasia tarda

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