Synpolydactyly (SPD) is a rare congenital limb disorder characterized by syndactyly between the third and fourth fingers and an additional digit in the syndactylous web.
Different limb malformations due to distinct classes of HOXD13 mutations should be considered as a continuum of phenotypes and further classification of syndactyly should be done based on phenotype and genotype.
In the family with complex brachydactyly and syndactyly, we detected a deletion of 21 bp in the imperfect GCN (where N denotes A, C, G, or T) triplet-containing exon 1 of HOXD13, which results in a polyalanine contraction of seven residues.
Heterozygous expansions of a polyalanine tract in HOXD13 are typically associated with synpolydactyly characterized by insertional digit duplication associated with syndactyly.
Synpolydactyly (SPD) is a dominantly inherited congenital limb malformation consisting of 3/4 syndactyly in the hands and 4/5 syndactyly in the feet, with digit duplication in the syndactylous web.
Variants in LRP4 have been previously associated with syndactyly in Cenani-Lenz syndactyly syndrome and Sclerosteosis 2, but have not been reported in individuals with isolated syndactyly.
These findings confirm that autosomal recessive loss-of-function mutations in Megf7/Lrp4 result in phenotypically similar forms of syndactyly in different mammalian species and that such mutations are the cause of MFD in bovines.
Reduced TFAP2A function causes variable optic fissure closure and retinal defects and sensitizes eye development to mutations in other morphogenetic regulators.
Karyotype-phenotype insights from 11q14.1-q23.2 interstitial deletions: FZD4 haploinsufficiency and exudative vitreoretinopathy in a patient with a complex chromosome rearrangement.