Associated anomalies in individuals with polydactyly

Abstract

An epidemiological analysis of the association of polydactyly with other congenital anomalies was performed in 5,927 consecutively born polydactyly cases. They were grouped into three categories: duplicated fifth digit, duplicated first digit, and rare polydactylies; also into isolated or associated groups, if other birth defects were or were not observed in the same infant. Associated cases were further subdivided into: combined, if the other defect was a limb defect; syndromic, if a non-limb defect constituted a recognized causal or pathogenetic entity; and MCA, if a non-limb defect did not constitute a recognized entity. In 14.6% of the 5,927 polydactyly cases studied, polydactyly was not the only congenital anomaly. This associated proportion was minimal for postaxial (11.8%), intermediate for preaxial-I (20.0%), and maximal for rare polydactyly (54.9%). Duplication of the fifth toe plus syndactyly of fourth and fifth toes, as well as other syndactylies adjacent to the duplicated digit is the most frequent type. Syndactyly of fourth and fifth toes was also combined with a duplicated fifth finger, suggesting the existence of an arrested or amputated in utero sixth toe. Polydactylies are rarely associated with other congenital anomalies except in recognizable syndromes. When syndromes are excluded, most of the significant positive associations disappear. Trisomy 13, Meckel, and Down syndrome explained 255 of the 338 syndromic polydactyly cases. Down syndrome is strongly associated with first-digit duplication, and negatively associated with postaxial polydactyly. The latter could not be explained by maternal age differences among Black and non-Black case sub-sets.

The chickoligozeugodactyly(ozd) mutant lacks sonic hedgehog function in the limb

“…The ozd mutation potentially affects a Shh regulatory element Disruptions in AP limb pattern are among the most common human birth defects (Castilla et al, 1996;Castilla et al, 1998), and understanding the affected developmental mechanisms is of significant clinical importance. Interestingly, studies in human and mouse have mapped several mutations and transgene insertions causing limb-specific AP patterning defects to a syntenic locus near or within the Limb region 1 (Lmbr1) gene, located less than 1 Mbp from the Shh coding region [ (Clark et al, 2001;Lettice et al, 2002), and references therein].…”

Why five fingers? Evolutionary constraints on digit numbers

“…Indeed, mutations for changes in the number of digits are associated with many serious abnormalities in mice, chickens and humans 22,[38][39][40] . Polydactyly is a characteristic of many human syndromes, such as Ellis van Crefeld, Bardet-Biedl, trisomy 13 and Down syndromes 4,41 . In 15% of babies born with an extra toe, other congenital abnormalities are also detected 4 , although in 85% of the babies with polydactyly, there are no associated anomalies.…”

“…Polydactyly is a characteristic of many human syndromes, such as Ellis van Crefeld, Bardet-Biedl, trisomy 13 and Down syndromes 4,41 . In 15% of babies born with an extra toe, other congenital abnormalities are also detected 4 , although in 85% of the babies with polydactyly, there are no associated anomalies. However, the problem in interpreting these data is that later medical problems are not usually recorded.…”

“…This is puzzling when one considers that mutations for POLYDACTYLY (see Glossary) are particularly common. In humans, for example, the most common anomaly at birth is the presence of an extra toe or finger 3,4 (0.l-0.2%). The extra digit can be rudimentary, or fully formed and functional.…”

Preaxial Polydactyly of Foot, Report of a Rare Case

“…Males and females are almost equally affected, and unilateral involvement is twice as common as bilateral involvement. Associated abnormalities of metatarsal commonly occur in polydactyly (10). Concomitant polydactyly of the hand occurs in one third and syndactyly of toes in one fifth of cases (2).…”