Fragile X syndrome and neoplasia

Among 100 males with fragile X [fra(X)] or Martin-Bell syndrome, two have developed malignancies. The first case, a 57-year-old man with fra(X) expression in 12% of peripheral blood lymphocytes, developed a seminoma of the left testis at age 45 years and in the right testis at age 50 years. The second case, a 16-year-old white boy with fra(X) expression in 23% of lymphocytes, developed a mucin-producing adenocarcinoma of the colon at age 14 years. Because of the unusual nature of the tumors observed in these patients and in 2 other patients from the literature, we suggest that individuals with the fra(X) syndrome may be at increased risk of cancer.