Knox (1959) suggested that "the patterns revealed by counting the numbers of aunts, uncles, and possibly other non-descendant relatives, offer a new means of characterizing some congenital abnormalities, and that these patterns are probably caused by the genetic or environmental factors which contribute to the occurrence of these diseases". It is not known whether non-specific mental subnormali...

We examined the social skills of adults with autism, PDDNOS, and mental retardation. All participants were diagnosed with profound mental retardation. Participants in the autism and PDDNOS groups had been previously diagnosed using the Childhood Autism Rating Scale (CARS) and record review. These diagnoses were confirmed by readministering the CARS by one author and an independent rater. Social...

A 3-year-old girl, her mother, and maternal uncle had microcephaly and mental retardation. Their facial appearance is characterized by deep-set eyes, short philtrums, and a "beaked" nose. The mother and uncle live in an adult foster care facility because of mental retardation. The 3-year-old girl has a developmental quotient of 55. Mother has normal phenylalanine level and the child's chromosom...

Introduction Fragile X Syndrome (FXS) is the most common form of inherited mental retardation, caused by a trinucleotide repeat expansion resulting in silencing of the fragile X mental retardation 1 (FMR1) gene in humans. The array of disorders caused by mutations in this single gene includes mental retardation and autistic behaviors. There is much evidence that the protein product, fragile X m...