Isolated postaxial polydactyly: Epidemiologic characteristics from a multicenter birth defects study

• Published in: American journal of medical genetics. Part A Vol. 179; no. 8; pp. 1432 - 1441
• Main Authors: Ortiz‐Cruz, Gabriela, Luna‐Muñoz, Leonora, Arteaga‐Vázquez, Jazmín, Mutchinick, Osvaldo M.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-08-2019; Wiley Subscription Services, Inc
• Subjects: Birth defects; Congenital defects; Consanguinity; epidemiologic characteristics; Epidemiology; isolated postaxial polydactyly; Limbs; Males; Minority & ethnic groups; multicenter study; Neonates; Polydactyly; Population studies; epidemiologic characteristics; multicenter study; isolated postaxial polydactyly
• ISSN: 1552-4825; 1552-4833
• DOI: 10.1002/ajmg.a.61193

Isolated postaxial polydactyly (I‐PAP), as a single defect, is a frequent malformation, characterized by an extra digit placed on the ulnar or fibular side of the limbs. Worldwide prevalence varies from as high as 225/10,000 in Nigerians to so low as 6.08/10,000 in Argentinians. Genetic–ethnic background significantly affects worldwide prevalence and type of I‐PAP. Herein we describe the epidemiological characteristics of I‐PAP in 697 newborns, 383 males and 314 females identified in 1,178,993 examined live births from a multicenter case–control hospital‐based population study, the Mexican program of Registry and Epidemiological Surveillance of Congenital Malformations (RYVEMCE). The main characteristics analyzed included total I‐PAP, stratified in Types A and B, defined as complete or incomplete extra‐digit formation, respectively, sex prevalence, affected limb, laterality, parity, prematurity, delivery‐type, twinning, consanguinity, and parental age. Males (6.35/10,000) are significantly more frequently affected than females (5.45/10,000), hands more than feet, left more than right limbs, and Type B (74.50%) more than A (25.50%). Prematurity and forceps use were significantly more frequent in cases than controls. An evident decreasing time‐trend prevalence was present. Similar findings with other studies were males, upper and left limbs more frequently affected. Findings that were not previously reported include prematurity, forceps use, a significant decreasing time trend and an inverse ethnic prevalence for Types A (75%) and B (25%) in the Mayan population in contrast to other worldwide ethnic groups.