Australia antigen, autoantibodies and cell-mediated immune responses in patients with Down's syndrome.

The prevalence of Au antigen, autoantibodies and impaired cell-mediated immune responses was studied in 66 patients with Down's sydrome and 66 other mentally retarded patients in a South Australian institution. The antigen was detected in three of the former and none of the latter. This unexpectedly low carrier rate in patients with Down's syndrome was thought to be due either to good hygiene and state of nutrition in the institution or to the high age of which the patients had been admitted to hospital (eight to nine years). Because of the incompleteness of the association between impairment of cell-mediated immunity and antigen carriage, it was thought unlikely that the former was the sole reason for the latter.     

Atlantoaxial dislocation and Down's syndrome.

The phenotypic features of Down's syndrome are easily recognized and include characteristic facial features, hypotonia, ligament laxity, transverse palmar creases and mental subnormality. Associated manifestations and complications are also familiar and involve almost every organ system. Congenital heart defects, bowel malformations and a tendency to leukemia are common attendant problems. Less common, however, are defects of the skeletal system; in fact, the most recent edition of a standard pediatric textbook makes no mention of anomalies of the vertebral column. The purpose of this paper is to call attention to the association between Down's syndrome and atlantoaxial dislocation, which in our patient resulted in quadriplegia and eventually death.     

Down's syndrome. Recent trends in the United States

The crude incidence of Down's syndrome (DS) in the United States is currently about 1/1,000 births. Reduction in the proportion of births to women 35 years and older can account for a halving of the estimated percentage of DS births to this age group and a drop in the estimated crude incidence of DS from 1.33/1,000 births in 1960 to 0.99/1,000 births in 1978. Epidemiologic studies suggest that among women 35 years and older, the risk of having a child with DS has not changed. With the present distribution of maternal ages, prenatal diagnosis among women 35 years and older can result in no more than a 20% decrease in the crude incidence of DS. With continued use of prenatal diagnosis among older gravidas, upward of 80% of DS births will occur to younger mothers.     

唐氏综合征筛查方法研究进展

唐氏综合征是一种最常见的常染色体疾病,是造成智力低下的重要原因。采用母体血清标记物进行唐氏综合征胎儿的筛查是一种非侵入性的检查方法,已成为近年来的研究热点。本文介绍了用于筛查唐氏综合征的各种母体血清标记物、各类筛查方案、筛查方法及影响因素。     

Counselling about Down's syndrome: the parents' viewpoint.

The parents of 50 children with Down's syndrome were interviewed to find what sort of information they were given at the time of diagnosis and what arrangements were made for the child's future. Particular emphasis was placed upon the method and timing of giving the parents the diagnosis, the utilization of community resources to help the family and what information they would have liked to have been given in retrospect. The ages of the children ranged between three months and eight years at the time of the survey. Seventy-two per cent of parents were given the diagnosis during the first week, with an increasing proportion being dissatisfied with the timing the longer the delay in telling what was wrong with the child. The mother has been told first in 48% of cases, and both parents have been told together in only 20% of cases. Fifty-four per cent of parents were encouraged to take the baby home, 22% were encouraged to place the baby in an institution, while in 28% of cases the decision was left to them. Forty-six per cent of patients felt that an overly-pessimistic outlook had been given by the doctor. Eighty-four per cent had medical follow-up, community follow-up, or literature supplied, whereas 16% had no such arrangements made. The parents' own suggestions for better management were sought. The two most outstanding were to be placed in early contact with community facilities and to be given a chance to meet other parents of children with Down's syndrome.     

Molecular diagnosis of Down’s syndrome

Objective To establish a new diagnostic method for Down’s syndrome using polymerase chain reaction (PCR).Methods DNA extracted from five healthy individuals and five Down’s syndrome patients was amplified in six specific tetranucleotide repeat loci on chromosome 21 using PCR. An accurate diagnosis was made by analyzing allelic distribution at each locus. Results All Down’s syndrome patients were identified as having at least two loci with three alleles, while none of the healthy individuals had three alleles. In addition, when two alleles were identified for a particular locus in the Down’s syndrome samples, it was more likely that the intensity ratio between the two alleles was close to 2∶1. Conclusion The molecular method can provide a fast, accurate, and economical alternation for the traditional cytogenetic diagnostic method for Down’s syndrome.