Two male patients with ring Y: definition of an interval in Yq contributing to Turner syndrome
- aDepartment of Medical Genetics, State University Hospital “Queen Giovanna”, 8 Bialo More Str, Sofia 1527, Bulgaria, bLaboratory of Molecular Pathology, University Hospital of Obstetrics, Sofia 1431, Bulgaria, cClinical Centre of Endocrinology, Medical University, Sofia 1303, Bulgaria, dCRC Chromosome Molecular Biology Group, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- Dr Tyler-Smith.
- Received 26 February 1998
- Revised 8 March 1999
Abstract
Turner syndrome is thought to result from the haploinsufficiency of genes on the sex chromosomes, but these genes have not been identified yet. We describe two males with deleted ring Y chromosomes, one (TS) with full Turner syndrome and one (DM) without. TS has short stature, skeletal anomalies, lymphogenic obstruction, cardiovascular abnormalities, and miscellaneous features including pigmented naevi, antimongoloid slanting of the palpebral fissures, and widely spaced nipples. In contrast, DM has short stature but no other specific Turner stigmata except high arched palate and a few pigmented naevi. Since little chromosomal mosaicism was detected, the different segments of the Y chromosome retained by these two males identify the location of one or more “anti-Turner” genes. Most of the Yp pseudoautosomal region and Yq were deleted from both patients during the formation of the ring chromosome, while the Y specific portion of Yp and the centromere were retained. The major difference detected was an interval of proximal Yq present in DM and deleted in TS. None of the previously identified genes, DFFRY, DBY, UTY, or TB4Y, lies entirely within this interval, although DFFRY was truncated by DM’s breakpoint. These data suggest that one or more additional “anti-Turner” gene(s) remains to be identified in the region of Yq proximal to DFFRY.
