The physical and behavioral features of the fragile X syndrome are reviewed in a paper from the Child Development Unit and Behavioral Sciences Department, Children’s Hospital, Denver. In the prepubertal child, macroorchidism means a testicular volume greater than 2 ml, documented in 39% of prepubertal fragile X males (Hagerman 1987). It is measured with an orchidometer, a string of ellipsoid shapes of known volume which can be matched for size next to the testicle. In the adult male, macroorchidism means a testicular volume of approximately 30 ml or larger. A broad spectrum of cognitive involvement occurs in both males and females affected by the fragile X syndrome. The majority of adult fragile X males are moderately retarded and function well in group homes and sheltered workshops; Whereas the majority of prepubertal males are mildly retarded and 10% have IQs in the borderline or low normal range, associated with significant learning disabilities. Language deficits are seen in all affected fragile X males, even those with a normal IQ. Speech is described as jocular or staccato, in bursts which may include perseverations or repetition of words or phrases. Longitudinal IQ evaluations of fragile X males have shown that younger boys score higher cognitively than adults. Heterozygous females may be completely unaffected by the syndrome or may have milder problems than those commonly seen in the males. Approximately 30% of heterozygotes have cognitive deficits ranging from a borderline IQ to more significant retardation. Heterozygotes with normal IQ (approximately 70%) have cognitive defects including a poor performance on Arithmetic, digit span and block design subtest scales on the WISC. Physical features in the mildly affected heterozygotes include prominent ears, double jointed thumbs, hyperextensible finger joints, and elongated face or prominent jaw in older females. Typical fragile X facial features are reported in 55% of retarded heterozygotes and in 14% of normal IQ heterozygotes. Enlargement of ovaries has been noted by ultrasound studies. [1]

COMMENT. This review article provides useful information about the clinical manifestations and psychopathology of heterozygous fragile X females. Careful examination will often reveal subtle physical features associated with the fragile X syndrome in females. Cognitive, social and emotional disorders are described. More detailed neuropsychological testing of heterozygotes has demonstrated learning disabilities in math, right left disorientation, constructional dyspraxia, and finger agnosia (Gerstmann’s syndrome). [2]