Keywords: Clinical Genetics, Malformations and Dysmorphology, KW008 - BONE/JOINT ABNORMALITIES, KW016 - CHARACTERIZATION OF SYNDROMES, KW022 - CLINICAL HISTORY, KW040 - ENDOCRINE SYSTEM, KW099 - NATURAL HISTORY

Low Serum Testosterone in Men with Marfan Syndrome. M. Burchett¹, B.F. Griswold², L. Sloper², C.A. Francomano³, S. Basaria⁴, N.B. McDonnell² 1) Centre Col, Danville, KY; 2) LCI, NIA/NIH, Baltimore, MD; 3) GBMC, Baltimore, MD; 4) CRB, NIA/NIH, Baltimore, MD.

   Marfan syndrome is a heritable disorder of connective tissue associated with cardiovascular and skeletal, and ocular abnormalities. Abnormalities of sex hormones in Marfan syndrome have not been noted previously. In six consecutive adult male subjects with Marfan syndrome, ages 25-52, enrolled at the National Institutes of Health, serum total testosterone values below the age norms were detected in research based testing. The lowest value was 155 ng/dL in a 31 year old man. Steroid hormone binding globulin (SHGB) was not elevated in any of the subjects. The subjects had normal sexual development and infertility was not noted. All subjects had decreased muscularity, a feature noted commonly in Marfan syndrome, as well as osteroporosis or osteopenia. One subject had suffered two vertebral compression fractures. Investigation of the pituitary axis in the Marfan syndrome cohort is ongoing in the study. Replacement therapy with exogenous testosterone was not initiated due to concern for cardiovascular consequences such as increase in blood pressure and progression of aortic root enlargement. Low serum sex hormones in Marfan syndrome may be a contributor to reduced bone density and increased fracture risk.