Fragile X syndrome: Growth, development, and intellectual function

Abstract

We collected data on growth, psychomotor development, speech and language development, and intellectual function on a cohort of 100 males with the fragile X chromosome and 95 carrier females. The data include information on prenatal growth (33 males), growth during the preadult years (32 males), psychomotor development during the first 2 years (25 males), speech and language development (15 males and 5 females), and intellectual function (93 males, 33 females, and 10 obligate carriers who were cytogenetically normal). Birth measurements appeared normal when plotted on the Usher/McLean curves of newborn infants (mean head circumference - OFC - at 40th centile, length at 60th centile and weight at 55th centile). Following birth, OFC rose above the 50th percentile and continued above average throughout the preadult years, whereas average length was above average for the first 5 years only and weight did not deviate from the normal mean. Psychomotor development lagged behind the norm from birth with affected males requiring nearly twice as long as expected to sit alone, walk unassisted, and say first words clearly. All males and females studied had significant language delay; all except one male had abnormalities of articulation. All on whom a clear voice sample was obtained had low voice pitch, and 80% had a hoarse or harsh quality of voice. Five males had word repetitions or perseverative speech during the preadult years. The mean IQ of the 93 males studied was 33 and regression analysis demonstrated a decrease in intellectual performance with age. Four fifths of the female carriers who expressed the fra(X) had intellectual performance in the mentally retarded range and showed similar decrease in performance with age. Obligate female carriers who did not express the fra(X) site had normal IQs (IQ 102 +/- 13.3).

Fragile X Syndrome: A Review of Associated Medical Problems

“…85,86 After birth, the head circumference tends to rise above the 50th percentile and continues to be larger than for male patients without FXS. 75,77,80,82,83,87 This is also reflected in the FXCRC data, where a larger head circumference was similar to that in other studies of adults with FXS. 75,87 For girls, Hagerman et al (1992) 88 found no difference in height, weight, or head circumferences of girls with FXS compared with relatives negative for the full mutation.…”

“…However, the overall proportion of infants with low birth weight was similar to that in the general population. The mean head circumference 80,81 and mean birth length 77,78,80,81 were not different from those of control populations.…”

Factors which contribute to cytogenetic frequency of expression in families of fragile X females

“…Jacobs et al [1980] also reported an association of IQ with proportion of fra(X) cells but re-examination of their data by Turner and Jacobs [1983] found no correlation of frequency of expression and IQ. Recently, however, Prouty et al [1988] observed an inverse relationship between IQ and frequency of expression among females.…”

Fragile X syndrome: A review of clinical management

“…After birth, the head circumference tends to rise above the 50 th percentile and continues to be larger than those without FXS. Jacobs et al noted that in six of nine affected men, the head circumference was greater than the 90 th percentile (18), but other studies have shown that the mean head circumference (19)(20)(21) and the mean birth length are not different of those of control population (21). Hagerman and colleagues found no difference in the height, weight or head circumference of girls with FXS compared with those without the full mutation (22).…”