{
  "abstract": "Objective This study aimed to investigate the prevalence of brachydactyly type A3 (BDA3) and its associated epiphysial development abnormalities in Chinese children aged 3–17 years, and to explore differences based on gender, region and urban–rural demographics.Design Cross-sectional study.Setting The study was conducted across 14 provinces (28 survey sites) in China, as part of a nationwide investigation on skeletal maturation. The population was selected using multistage stratified randomised cluster sampling.Participants A total of 17 850 children (8856 boys and 8994 girls) aged 3–17 years participated. The cohort was drawn from a large-scale survey conducted between 2019 and 2021. Selection criteria included children with no visible clinodactyly or hand function impairments.Methods Non-dominant hand-wrist radiographs were obtained using a portable X-ray device. A retrospective analysis of these radiographs was performed to identify BDA3 and epiphysial development abnormalities. Prevalence rates were calculated and compared across gender, regional and urban–rural groups.Results The overall prevalence of BDA3 was 10.0%, with a higher prevalence in girls (12.9% vs 7.1%; p<0.001). The northern region exhibited a higher prevalence compared with the southern region (11.5% vs 8.6%; p<0.001). No significant differences were observed between urban and rural areas (10.3% vs 9.8%; p=0.32). Among the BDA3 phenotypes, brachymesophalangia-5 with cone-epiphysis of mid-5 (BMP5) and BMP5 alone had prevalences of 3.6% and 6.4%, respectively. Both phenotypes were more common in girls compared with boys (p<0.001 for both).Conclusions This nationwide, multicentre study provides the first national epidemiologic data on BDA3 and associated epiphysial features in Chinese children and adolescents, establishing a prevalence of 10.0%. This baseline supports counselling that a straight, well-functioning short fifth finger is a common anatomic variant and may help reduce unnecessary concern.",
  "authors": [
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China",
        "Department of Radiology, Peking University Fourth School of Clinical Medicine, Beijing, China"
      ],
      "name": "Wenshuang Zhang"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Kai Li"
    },
    {
      "affiliations": [
        "National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, China"
      ],
      "name": "Qian Zhang"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Jian Geng"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China",
        "JST Sarcopenia Research Centre, National Center for Orthopaedics, Beijing Research Institute of Traumatology and Orthopaedics, Beijing Jishuitan Hospital, Capital Medical University, Beijing, China",
        "AI laboratory for Orthopaedics lmaging, Beijing lishuitan Hospital, Capital Medical University, National Centre for Orthopaedics, Beijing, China"
      ],
      "name": "Ling Wang"
    },
    {
      "affiliations": [
        "National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, China"
      ],
      "name": "Zhenyu Yang"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Wenhai Wang"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China",
        "Department of Radiology, Peking University Fourth School of Clinical Medicine, Beijing, China"
      ],
      "name": "Yi Yuan"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Yandong Liu"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Bo Hu"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Fengyun Zhou"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Zitong Cheng"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China",
        "Department of Radiology, Peking University Fourth School of Clinical Medicine, Beijing, China"
      ],
      "name": "Qingyu Zhang"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China"
      ],
      "name": "Dong Yan"
    },
    {
      "affiliations": [
        "National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, China"
      ],
      "name": "Wenhua Zhao"
    },
    {
      "affiliations": [
        "Department of Radiology, Beijing Jishuitan Hospital, Capital Medical University, National Center for Orthopaedics, Beijing, China",
        "Department of Radiology, Peking University Fourth School of Clinical Medicine, Beijing, China"
      ],
      "name": "Xiaoguang Cheng"
    },
    {
      "affiliations": [
        "School of Biomedical Engineering & Imaging Sciences, King's College London, St Thomas' Hospital, London, UK"
      ],
      "name": "Glen M Blake"
    }
  ],
  "title": "Epidemiology of brachydactyly type A3 in China: a nationwide multicentre population-based study among children aged 3–17 years",
  "uid": "725ed839-5684-516b-a94c-6e9260edb430"
}