Results: The pedigree showed X-linkage recessive inheritance pattern, and pathogenic mutation (c.499C>T) was identified in the proband and his family member, which led to a premature termination prior to the entire POU domains.
The five-generation pedigree presented with an X-linkage recessive inheritance pattern of hearing loss.
The Prune Belly anomaly: heterogeneity and superficial X-linkage mimicry.
But it has recently been suggested that it is a 2 step autosomal dominant mutation with sex-linked expressions, partially mimicking X-linkages (7).
In other words, the Ashton study did not find a complete pattern suggestive of possible X-linkage. The Risch and Pringle (1985) sample did produce results largely consistent with X-linkage, since they found no significant difference in the handedness distribution of sons born to RL and RR couples, while at the same time finding a significantly higher incidence of left-handedness of daughters born to RL than to RR couples.
Except for the latter findings the results of the Risch and Pringle study are entirely consistent with present findings, although, as noted above, these investigators never mentioned the fact that some of their results were consistent with X-linkage.
A basic objection to X-linkage as the sole genetic influence on human handedness is that is predicts a much higher rate of left-handedness in males than in females, when actual data show that left-handedness is significantly, but rather slightly, more common in males than females.