Compound heterozygous female with fragile X syndrome

We report on a 15-year-old compound heterozygous young woman with fragile X syndrome who has a full mutation of 363 repeats on one X chromosome and a premutation of 103 repeats on the other X chromosome, As predicted, subsequ ent testing demonstrated that her father carries a premutation (98 repeats) as does her mother (146 repeats). There is only one previous report of a c ompound heterozygous female with fragile X syndrome. By quantitation of Sou thern blot signals, the activation ratio for the premutation (the proportio n of the premutation on the active X chromosome) was determined to be 0.78. Immunocytochemistry of blood smears showed fragile X mental retardation-1 protein (FMRP) expression in 63.5% of lymphocytes, Cognitively,this woman i s functioning: in the midrange of involvement for fragile X females. She at tends regular classes and receives supplemental assistance for her learning disabilities. She experiences behavior characteristics typical of females with fragile X syndrome including severe shyness, anxiety, panic episodes, mood swings, and attention deficits. She has responded very well to appropr iate treatment including fluoxetine for anxiety, methylphenidate for attent ional problems, and educational therapy. (C) 1999 Wiley-Liss, Inc.