Mohr-Wriedt (A2) brachydactyly: analysis of a large Brazilian kindred.

A large Brazilian kindred of German origin with 117 individuals with the A2 (Mohr-Wriedt) bradydactyly is presented. Some drawings based on radiographs and revealing the high phenotypic spectrum of the malformation are presented. Our corrected data suggest the presence of a segregation distortion in favor of the affected among the daughters of affected mothers (45:25; x12 = 5.71). This apparent anomalous segregation is not significant in the other comparisons made, although the p values corresponding to the x12 for two of them (78:56 and 109:83) are near 5%. Other 'similar' (although possibly different on the genetic aspect) A2 cases in the literature do not present any evidence of anomalous segregation. The dermatoglyphic disturbances verified in the affected index fingers seem to be mere allophenes of the basic dysmorphogenetic process which leads to the (autophenic) bone malformations. There is no birth order effect on the affected. Fertility seems to be higher among them than among their normal sibs.