Tissue-specific methylation differences and cognitive function in fragile X premutation females.

Tissue-specific variation in (CGG)n repeat size and methylation status of the FMR1 gene was investigated in 17 female premutation carriers. Minor variation in premutation repeat size among leukocyte, lymphoblast, and fibroblast tissues was noted in some subjects. One subject exhibited a premutation size allele of (CGG)64 in leukocyte and fibroblast tissues by polymerase chain reaction analysis but a normal-size allele of (CGG)46 in lymphoblast cells, suggesting low-level mosaicism in blood and clonality of the lymphoblast cell line. Six subjects exhibited differences in methylation pattern between leukocytes and lymphoblasts but not between leukocytes and fibroblasts, whereas 2 subjects showed large differences in methylation pattern between leukocytes and fibroblasts. Cognitive function was studied in 14 subjects using the Wechsler Adult Intelligence Scale-Revised. Mean Verbal and Performance IQs were well within the average range as was the mean Full Scale IQ; nevertheless, a trend toward lower Performance IQ compared with Verbal IQ was observed. No significant correlation was apparent between Full Scale IQ and (CGG)n repeat size; however, a significant positive correlation was observed between Full Scale IQ and the proportion of the active X carrying the normal FMR1 allele in fibroblasts but not in leukocytes or lymphoblasts.

Long-term neurological sequelae of hemolytic-uremic syndrome: a preliminary report.

Seven patients with hemolytic-uremic syndrome who had major neurological symptoms during the acute illness were neurologically and cognitively evaluated prospectively several years after recovery from the illness. Four patients showed evidence of subtle neurological sequelae, including posturing, clumsiness, poor fine-motor coordination, hyperactivity, and distractibility. Psychoeducational evaluation of all seven subjects revealed mean scores within the average range in cognitive abilities, academic achievement, single word receptive vocabulary, visual/motor planning, overall adaptive functioning, and hyperactivity. The lapse of time (minimum of 7 years) between the acute illness and the psychometric evaluation could have been responsible for our normal results.

Evidence of nonverbal learning disability among learning disabled boys with sensory integrative dysfunction.

The presumed sensorimotor basis of the nonverbal learning disability syndrome was investigated among 90 learning disabled boys (M age = 6 yr., 8 mo., SD = 12.2 mo.) with sensory integrative dysfunction. The majority of the boys were Caucasian, lower to middle socioeconomic status, and from urban, English-speaking families. 14% (n = 13) of the boys satisfied core discrepancy criteria for nonverbal learning disability, including both a significantly higher Wechsler Verbal than Performance IQ and a higher standard score in Reading than Arithmetic on the Wide Range Achievement Test. Compared with a control group of 19 boys from the same sample who had no significant discrepancies, boys with nonverbal learning disability had significantly greater weaknesses in space visualization and visuomotor coordination. As predicted, rote verbal memory and syntactical strengths were also exhibited by boys with nonverbal learning disability, but the two groups did not differ significantly.

Savant characteristics in a child with developmental delay and deletion in the short arm of chromosome 20.

The development outcome of a four-year-old boy with a deletion of the short arm of chromosome 20 is described. Despite a number of early medical problems, including infantile hypoglycemic convulsions secondary to growth hormone deficiency and delayed motor and language development, he has been reading (self-taught) since 2.5 years and currently has computer proficiency, and exceptional memory for maps and spatial locations, an extremely rich and active fantasy life, good diction, and an extensive spoken vocabulary. Neuropsychological evaluation revealed low-average intelligence with normal language, memory and attention functions, and impaired visuomotor and graphomotor ability and motor skills. He showed extremely advanced decoding and reading comprehension skills while mathematics, spelling and general knowledge abilities were average.