Similarities arise in developmental syndromes.

BALTIMORE -- Children with fragile X syndrome, Williams-Beuren syndrome, and neurofibromatosis type 1 show some similarities in cognitive profiles and high levels of maladaptive behaviors, said Gene Fisch, Ph.D.

And children with fragile X and Williams-Beuren syndromes showed significant declines in both IQ and behavior scores as they got older, while children with neurofibromatosis type 1 did not.

"It's typically the case that the genetic abnormalities produce particular cognitive-behavioral profiles," Dr. Fisch said at a meeting on developmental disabilities sponsored by Johns Hopkins University.

Dr. Fisch and his colleagues collected baseline data on 108 children aged 4-15 years, including 44 children with fragile X syndrome (FRAXA), 34 children with Williams-Beuren syndrome (WBS), and 30 children with neurofibromatosis type 1 (NF1).

The investigators used the Stanford-Binet test to evaluate the children's cognitive abilities and the Vineland Adaptive Behavior Scales to evaluate the children's adaptive and maladaptive behaviors.

The goal was to compare and contrast the cognitive abilities and the adaptive and maladaptive profiles of children diagnosed with these three developmental conditions, according to Dr. Fisch of the New York University College of Dentistry.

This study is ongoing and he has been following the children and evaluating them periodically for almost 20 years.

The mean baseline IQ scores were approximately the same between children with WBS and children with FRAXA (52.1 vs. 51.3).

The mean IQ score for the NF1 children was 88.3.

Increasing age has been significantly correlated with lower IQ scores in children with Williams-Beuren syndrome and FRAXA, but not with NF1.

"But age-related declines in scores are not necessarily a sign of recession," Dr. Fisch noted.

The declines indicate that the children are falling further behind other children their age, he explained.

Similarly, the mean baseline DQ scores (a measure of adaptive behavior) were approximately the same between WBS and FRAXA children, and these scores have declined with increasing age.

The mean baseline DQ score for the NF1 children was 81.9, statistically significantly higher than for either WBS or FRAXA children.

NF1 scores have remained relatively stable over time.

Although the mean baseline IQ and DQ scores were higher in the NF1 children compared with the FRAXA and WBS children, the cognitive profiles are similar among the groups, Dr. Fisch said. All three groups have shown similar relative strengths in verbal reasoning and quantitative reasoning, and relative weaknesses in visual/spatial reasoning and short-term memory.

The behavior profiles of these developmental conditions, however, are "a bit of a grab bag," Dr. Fisch said.

Maladaptive behavior is common among many children with any of these three genetic disorders, according to Dr. Fisch.

Based on his findings, the greatest decline in adaptive behavior over time appears to occur in children with WBS.

Research suggests that different areas of the brain may be affected in each syndrome, but more studies are needed to better identify the similarities and differences in adaptive and maladaptive behaviors among children with specific genetic abnormalities.

Studying the cognitive-behavioral profiles and age-related features of these deficits can help clinicians make inferences about how brain development may relate to cognitive ability as a child ages, he said.

Dr. Fisch stated that he had no financial conflicts of interest to disclose.

BY HEIDI SPLETE

Senior Writer