A large Turkish kindred with syndactyly type II (synpolydactyly). 2. Homozygous phenotype?
نویسندگان
چکیده
Syndactyly type II (synpolydactyly (SPD)) is an autosomal dominant condition with typical abnormalities of the distal parts of both upper and lower limbs. We report here a previously undescribed phenotypic feature of people with severe hand and foot deformities who were born to two affected parents. This is the first example of SPD subjects manifesting a very distinctive phenotype, suggesting that they must be homozygous for this condition. The typical characteristic clinical features in these subjects are as follows: (1) short hands with wrinkled fatty skin and short feet; (2) complete soft tissue syndactyly involving all four limbs; (3) polydactyly of the preaxial, mesoaxial, and postaxial digits of the hands; (4) loss of the normal tubular shape of the carpal, metacarpal, and phalangeal bones, so as to give polygonal structures; (5) loss of the typical structure of the cuboid and all three cuneiform bones while the talus calcaneus and navicular bones remain intact; (6) large bony islands instead of metatarsals, most probably because of cuboid-metatarsal and cuneiform-metatarsal fusions; and (7) severe middle phalangeal hypoplasia/aplasia as well as fusion of some phalangeal structures that are associated with the loss of normal phalangeal pattern. We report seven subjects with this phenotype from three different branches of a very large SPD pedigree exhibiting the same phenotype with minimal variation. In mice, the Polysyndactyly (Ps) mutation shows a pattern of synpolydactyly very similar to that of human SPD, suggesting that they may well be homologous mutations. A molecular genetic study is currently under way to determine the chromosomal location of the SPD locus in humans and to identify the corresponding homologous region in mice.
منابع مشابه
Functional classification and mutation analysis of a synpolydactyly kindred
The aim of the present study was to analyze a congenital syndactyly/polydactyly kindred and propose a new functional classification method of clinical significance. The modes of inheritance and mutational mechanisms were also determined using genetic analyses. Hand and foot anatomy and functions were measured using photographic images, X-ray imaging and grip ability tests. Genetic analysis comp...
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A new family with syndactyly type II or synpolydactyly is described with 16 affected members in six generations. No other major skeletal or extraskeletal malformations were present, but the association with minor local anomalies may be a common feature. Various metacarpal or metatarsal abnormalities may be part of this type of syndactyly. The family pedigree confirms the autosomal dominant mode...
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ورودعنوان ژورنال:
- Journal of medical genetics
دوره 32 6 شماره
صفحات -
تاریخ انتشار 1995