Deletions in Xq28 in two boys with myotubular myopathy and abnormal genital development define a new contiguous gene syndrome in a 430 kb region

We have recently described a female patient with myotubular myopathy (MTM1) and an interstitial deletion at Xq28. Characterisation of the deletion allowed us to position the MTM1 gene to a 600 kb region between DXS304 and DXS497. In order to further restrict the region we screened for deletions in a set of 38 patients. We found two overlapping deletions in boys that in addition to MTM1 showed an unexpected abnormal genital development. As the latter phenotype is not found in the other non-deleted MTM1 patients, our observations are best explained by a contiguous gene syndrome. The deletions define a 430 kb region that contains the MTM1 gene and most likely a gene implicated in male sexual development. A high resolution physical map of this region is presented.