Date of Award
Doctor of Philosophy
Abnormal testicular volume can be associated with various mental retardation (MR) syndromes. For example, bilateral testicular enlargement with no evidence of any endocrinological disturbance has been described in some families with non-specific X-linked MR, both fragile X positive and negative. In contrast, a fragile X negative kindred with non-specific X-linked MR in which affected males had small to normal size testes has also been reported. Based on these reported observations, the present study was initiated to determine the usefulness of abnormal testicular volume as a clinical marker in the cytogenetic evaluation of MR syndromes.;The testes of institutionalized, non-Down syndrome males were measured with sliding calipers for the determination of testicular volume (V).;Cytogenetic investigations revealed an overall frequency of 3.1% for the fragile X syndrome among institutionalized (non-Down syndrome) males. A significantly higher proportion of macro-orchid males (10.3%) had the fragile X as compared to males with either micro-orchidism (1.2%) or normal testicular volume (1.2%).;Examination of the medical records of fragile X negative probands showed that a further 10.4% of institutionalized (non-Down syndrome) males had a family history of MR which was suggestive of fragile X negative non-specific X-linked MR. There was no significant difference in the distribution of fragile X negative non-specific X-linked MR in males with macro-orchidism (10.9%), micro-orchidism (9.7%) or normal testicular volume (9.1%). The preferential association of macro-orchidism with the fragile X syndrome clearly establishes the use of enlarged testicular volume as a clinical marker in the diagnosis of this MR syndrome.;Chromosome abnormalities other than the fragile X were found in 3.6% of institutionalized (non-Down syndrome) males. Although a large number of the chromosome anomalies detected in this study were found in micro-orchid males, there was no significant difference in the distribution of non-fragile X chromosome abnormalities between males with micro-orchidism (4.2%), macro-orchidism (2.4%), and normal testicular volume (3.0%). A significantly greater number of micro-orchid males (39.8%) were found to have spastic/paralytic disorders as compared to males with either macro-orchidism (4.2%) or normal testicular volume (15.6%). The above findings show that micro-orchidism is not a useful clinical marker in the evaluation of MR males with possible chromosome abnormalities. (Abstract shortened with permission of author.)
Kirkilionis, Angelika Jurate, "Testicular Volume And Its Correlation With The Cytogenetics Of Mental Retardation" (1985). Digitized Theses. 1474.