Genomic coordinate 9:91,722,601
Here I present: “Brachydactyly Type-B1“, Victor McKusuck, Mendelian Inheritance in Man’, 1966. (ROR2) 短指症B1型。icd10=Q73.8
INTRODUCTION.
Brachydactylytype type-B1 characterized by hypoplasia or aplasia of the distal phalanges of digits 2-5 with or without nail dysplasia, in association with fusion of the middle and distal phalanges, a broad or bifid thumb, and occasionally distal and proximal symphalangism or syndactyly. The feet are less severely affected than the hands.
Brachydactyly type-B1 (BDB1) is the most severe type of human brachydactyly, and shows high penetrance and variable expressivity. Hypoplastic or absent distal phalanges and nails of digits 2 through 5 in the hands and feet are cardinal phenotypic features of BDB1. The middle phalanges of digits 2 through 5 are usually short and may form a bony fusion with the corresponding hypoplastic distal phalanges. The deformed thumbs are often flat, broad, or bifid. A rarer feature of BDB1 is cutaneous syndactyly affecting both fingers and toes.
There is evidence that brachydactyly type-B1 is caused by heterozygous mutation in the receptor tyrosine kinase (ROR2) gene on cytogenetic location 9q22.31 and genomic coordinate 9:91,722,601.
