Hand and foot postaxial polydactyly: two different traits.

Abstract

The aim of this work was to test whether postaxial hexadactyly had different clinical and epidemiological characteristics depending on hand or foot involvement. In the period 1967-1993, the Latin-American Collaborative Study of Congenital Malformations (ECLAMC) enrolled 1,582,289 births, and 2,271 cases with isolated (nonsyndromal) postaxial polydactyly (5th-digit hexadactyly). The prevalence was 14.3/10,000 births. Postaxial polydactyly (PP) of the hand (HPP) was the most frequent type (N:1,733; 76.3%; prevalence: 11.0/10,000), followed by foot PP (FPP=N:351; 15.5%; prevalence: 2.2), and hand and foot PP (BPP=N:187; 8.2%; prevalence: 1.2). Unlike HPP (55.0% bilateral; 77.2% left), FPP was less frequently bilateral (19.4%), with lower preference for the left side (55.5%). As expected, HPP was associated with African Black ethnicity, male sex, twinning, low maternal education, parental consanguinity, and there was frequent recurrence in 1st-degree relatives. Conversely, FPP was associated with Amerindian racial background, parental subfertility, and bleeding in the 1st trimester of pregnancy. BPP displayed the highest frequency of associated congenital defects (23.4%, vs HPP:6.6%, FPP: 15.4%). In its isolated form, BPP resembled HPP more than FPP with respect to left preference (90.9%), familial recurrence (11.0% of 1st degree relatives), and low maternal education. Although male sex preference and high frequency of twinning was observed in the 3 PP subtypes, statistical significance was present only in HPP. None of the 3 PP subtypes showed abnormal values for perinatal mortality, birth weight, length of gestation, parental ages, or parity. A logistic regression analysis showed Black race only to be associated with HPP, parental subfertility with FPP, parental consanguinity with BPP, and non-Black race with both FPP and BPP. The data presented here are the first indication that HPP and FPP are 2 different entities, with a larger genetic component in HPP than in FPP.

• Authors: E E Castilla, M da Graca Dutra, R Lugarinho da Fonseca, J E Paz
• Journal: American journal of medical genetics (Am J Med Genet) Vol. 73 Issue 1 Pg. 48-54 (Nov 28 1997) ISSN: 0148-7299 [Print] United States
• PMID: 9375922 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Ethnicity (genetics)
• Female
• Foot Deformities, Congenital (epidemiology, ethnology)
• Hand Deformities, Congenital (epidemiology, ethnology)
• Humans
• Likelihood Functions
• Male
• Phenotype
• Polydactyly (epidemiology, ethnology)
• Pregnancy
• Prevalence
• Sex Characteristics