Prevalence of autism in an urban population of adults with severe intellectual disabilities--a preliminary study.

BACKGROUND: Research on the prevalence of autism in Iceland has indicated that one possible explanation of fewer autism cases in older age groups was due to an underestimation of autism in individuals with intellectual disabilities (IDs). The present study systematically searched for autism cases in the adult population of individuals with severe ID living in the city of Reykjavik, Iceland. METHODS: Potential participants (n = 256) were recruited through the Regional Office for the Affairs of the Handicapped in Reykjavik. First, a screening tool for autism was applied, followed by the Childhood Autism Rating Scale and finally the Autism Diagnostic Interview-Revised (ADI-R). RESULTS: The point prevalence of severe ID was 3.7/1000 (95% CI 3.2-4.1) with a male-female ratio of 1.2:1. Participation rate in the study was 46.5%. Participants were younger than non-participants and more often residents of group homes. The prevalence of autism was 21% (25/119) (95% CI 14.7-29.2) with a male-female ratio of 1.8:1. Of the individuals with autism, 10/25 (40%) were verbal according to the ADI-R definition, and 18/25 (72%) had active epilepsy and/or other neurological conditions and handicaps. CONCLUSION: The study identified twice the number of autism cases than those previously recognised within the service system. Autism is a prevalent additional handicap in individuals with severe ID, which should always be considered in this population. There are indications that the estimated prevalence of autism found should be considered minimal.

Age of walking in the cognitively impaired.

Age levels for independent walking were compared for groups of children with varying degrees of intellectual impairment, but without other neurologic handicaps. All walked independently, save for 13.5 per cent of the profoundly retarded. Although mental retardation was associated with a delay in walking, subgroups existed at all levels that walked at a normal age. This suggests that the cognitive level is not the sole determinant for the achievement of this milestone.

Distal monosomy 14 not associated with ring formation.

A 12-year-old boy with congenital heart disease, short stature, mildly dysmorphic facies, and mild intellectual impairment was found to have a de novo terminal deletion (14)(q32.3). Although his phenotype resembles that of six reported patients with a similar breakpoint, his CNS involvement is milder. He appears to be the first reported case of a terminal deletion of chromosome 14 not associated with ring 14 formation. Advanced parental ages and maternal origin of the chromosome with the deletion are noted.

A syndrome of progressive pancytopenia with microcephaly, cerebellar hypoplasia and growth failure.

A male infant with congenital thrombocytopenia, progressing to pancytopenia in the second year of life is presented. Other findings included microcephaly with cerebellar hypoplasia, growth failure of prenatal onset and severe psychomotor retardation. He died at 23 months of age from candida albicans septicemia. Laboratory studies and a postmortem examination failed to reveal any known etiology for his disorder, but parental consanguinity suggests a genetic basis with an autosomal recessive mode of inheritance. Høyeraal et al. have previously reported two brothers with similar clinical and laboratory findings. It is proposed that the condition of these three patients should be considered as a separate syndrome of congenital pancytopenia, distinguished from other congenital myeloid dysplasias by the extramedullary findings.

A family showing apparent X linked inheritance of both anencephaly and spina bifida.

A family is reported which includes five males, two with spina bifida, two sibs with anencephaly, and one with both high and low spinal lesions. The affected subjects came from four sibships in three generations. The mode of inheritance of these neural tube defects is consistent with X linkage.

Copper, ceruloplasmin and superoxide dismutase (SOD1) in patients with Down's syndrome.

The aim of this study was primarily to investigate whether similar signs of copper dyshomeostasis occur in dementia with age in Down's syndrome as previously found in Alzheimer's disease. Copper was accordingly determined in plasma, ceruloplasmin concentration in serum, ceruloplasmin oxidative activity and ceruloplasmin specific oxidative activity (activity related to mass) in serum, and superoxide dismutase (SOD1) in erythrocytes in 35 (27 males, 8 females) 18-53 years old (average 37 years) patients with Down's syndrome (Down's patients) and their age- and gender-matched controls. SOD1 activity was on an average almost 50% higher in the patients than in their controls but the evidence of a causal relationship between increased SOD1 activity and Down's syndrome appears at best equivocal. Copper and ceruloplasmin levels and ceruloplasmin activities were similar in the patients and their controls. Ceruloplasmin and copper levels increased significantly with age in the patients but not in the controls. Ceruloplasmin activities or SOD1 activity did not change significantly with age, neither in the patients nor in the controls as whole groups. When SOD1 activity and ceruloplasmin activities of the oldest in the patients group (40 years or older) were compared with those of the younger patients, respectively, SOD1 activity and specific oxidative activity, but not ceruloplasmin oxidative activity were found to decrease significantly with age. The results thus suggest that development of dementia in Down's patients with age is paralleled with decrease in SOD1 activity and specific oxidative activity but not with decrease in ceruloplasmin oxidative activity itself as was also found in Alzheimer's patients.

Aspartylglucosaminuria in the United States.

Aspartylglucosaminuria (AGU) was diagnosed in two unrelated males with progressive mental retardation, coarse facies and skeletal abnormalities. Until now, this disorder has been described in predominantly Finnish populations with only one previous case reported in the U.S. We conclude that AGU may be more common in non-Finnish populations than the number of reported cases would indicate and should be included in the differential diagnosis in patients with suspected lysosomal storage disorders regardless of their geographical or ethnic backgrounds.

Impaired cerebroside sulfate hydrolysis in fibroblasts of sibs with "pseudo" arylsulfatase A deficiency without metachromatic leukodystrophy.

Low arylsulfatase A levels are reported in two siblings, one with a neurologic disability not typical for metachromatic leukodystrophy, the other a healthy 18-year-old female with a normal developmental history. In both individuals, arylsulfatase A levels in white blood cells were 7-8% of control values. Cultured fibroblasts gave low values (8-10% of normal) for both cerebroside sulfatase and arylsulfatase A activities. Other family members had enzyme levels consistent with heterozygote or normal status. Cerebroside sulfate loading tests of cultured fibroblasts in 199-CO2 media were normal for all family members who were tested. In MEM-HEPES media, however, cells from the two arylsulfatase A deficient siblings showed attenuated sulfolipid catabolism. Additional clinical and laboratory studies on these individuals failed to demonstrate any features suggestive of metachromatic leukodystrophy, i.e., normal nerve conduction velocities, normal sural nerve biopsy results, and normal urinary sulfatide excretion. It is concluded that the neurologic abnormalities in the one sibling are not the result of the low enzyme activity and that both individuals represent examples of pseudo arylsulfatase A deficiency (arylsulfatase A deficiency without metachromatic leukodystrophy). These results thus call into question the ability of the high-sensitivity cerebroside sulfate loading test as carried out in MEM-HEPES media to differentiate pathologically significant defects i.e., metachromatic leukodystrophy from benign "pseudo-deficiencies."