The methodology of many studies that have identified specific genetic loci for disorders associated with mental retardation is criticized as failing to demonstrate an association between the behavior phenotype and the genetic marker. A more appropriate methodology using a multitrait-multimethod approach is suggested. (Author/JDD)

Three models of behavioral effects of genetic disorders characterized by mental retardation were compared: (1) no-specific effect model (all genetic disorders have identical behavioral outcomes); (2) totally specific model (each genetic disorder has unique outcomes); and (3) partially specific model (two or more genetic disorders share outcomes…

This study compared maladaptive behavior in 23 people with Prader-Willi syndrome due to paternal deletion and in 23 age- and gender-matched subjects with maternal uniparental disomy. Controlling for IQs, the deletion cases showed significantly higher maladaptive ratings, more symptom-related distress, and more behavior problems. Findings suggest a…

A survey of the families of 62 persons with Prader-Willi syndrome examined the prevalence, topographies, and specific body locations of self-injurious behaviors. Self-injury was reported for 81% of the participants. Skin-picking was the most prevalent form with the front of the legs and head being disproportionately targeted. Incidence also varied…

Evaluation of the cognitive, behavioral, and adaptive functioning of 12 retarded men with fragile X syndrome indicated that fragile X men were largely indistinguishable from comparison groups. They were, however, significantly more likely to have achieved levels of adaptive functioning commensurate with their intellectual abilities. (Author/DB)

This paper considers key properties of behavioral phenotypes of mental retardation syndromes, including within-syndrome variability and between-syndrome similarities and qualitative differences. The "new genetics" research requires combining data from three strategies: (1) a psychiatric approach, (2) psychometric methods, and (3) syndrome-specific…

The social development of a female rhesus monkey was followed from birth until death, age 32 months. The monkey had an extra autosome and was hydrocephalic. The monkey showed serious motor deficiencies, delayed social development, poorly established dominance relationships, and heavy dependence on mother and kin. The monkey was, however, well…

This study examined Autism Diagnostic Interviews Revised (ADI-R) data for 69 autistic subjects from multiplex (MP) families (with more than one autistic member) and 88 autistic subjects from singleton (SP) families (with only one autistic member). Multivariate analysis revealed no differences between verbal or nonverbal MP and SP groups for ADI-R…

This article examines the status of behavioral research on genetic mental retardation syndromes and finds that the field continues to struggle with three methodological issues: (1) how to think about control or contrast groups, (2) the interplay of behavioral phenotypes with development and other within-group variations, and (3) the efficacy of…