Descriptive epidemiology of hereditary musculoskeletal and limb defects in the isolated population of Chitral, North-West Pakistan

OBJECTIVES: Musculoskeletal and limb defects (MLDs) are the major categories in hereditary anomalies and are a significant source of the disabilities. This study aimed at elucidating the nature and pattern of MLDs prevalent in Chitral district, which is an isolated population in the North-West of Pakistan. METHODS: A cross-sectional epidemiological study was conducted in Chitral and subjects/families with MLDs were ascertained from public places, hospitals and door-to-door visits. The phenotypic manifestations, expressivity, sporadic/familial presentations, isolated/syndromic nature, inheritance pattern, and socio-demographic attributes, of MLDs were observed. RESULTS: A total of 153 independent subjects/families with certain types of MLDs were recruited. The MLDs were classified into 9 major and 22 minor entities. In this cohort, polydactyly was observed to be overwhelmingly common (71%), followed by syndactyly and absence limb deformities. The majority of the cases (78%) had sporadic nature, 93% anomalies had isolated presentations; upper limbs were more commonly affected than the lower limbs; and unilateral cases were twice in ratio than bilateral. The majority of the malformations had milder phenotypes, however, 17% of the MLDs were severe in nature and resulted in certain types of disability, compromising the normal life of the subject. CONCLUSION: This research witnesses a distinctive pattern of MLDs in Chitral, which has not been reported for any other population of Pakistan so far. Further studies are required to observe the molecular etiologies of these malformations and to offer rapid diagnosis and genetic counseling.