The distribution of Down's syndrome

Mothers of children with Down syndrome have higher herpes simplex virus type 2 (HSV-2) antibody levels

The antibody response to herpes simplex virus (HSV) was studied in 53 mothers of children with Down syndrome (Ds) and compared with that in 154 controls, using sera sampled during pregnancy or at delivery. Conventional analysis of HSV complement fixing antibodies showed the same frequency of positivity for the two groups (70%). When the levels of IgG antibodies to an HSV-1 and an HSV-2 antigen preparation were determined by an enzyme-linked immunosorbent assay (ELISA) technique, it was found that the Ds and control mothers had similar levels of IgG antibodies to HSV-1, whereas the level of IgG antibodies to HSV-2 was significantly (P less than 0.001) higher in Ds mothers. The ratio of HSV-2 to HSV-1 ELISA IgG was calculated for each mother and the distribution of these ratios also differed significantly between the control and Ds mothers. The differences found were not due to differences in age distribution in the control and Ds groups. For comparison a third procedure, measurement of thymidine kinase blocking antibody (TK ab), was used. With this procedure the mothers were divided into groups estimated to be positive for HSV-1, HSV-2, or both. Statistical analyses showed a good correlation between the type found in TK ab analyses and the ratio found in the ELISA HSV test. The results clearly demonstrated an overrepresentation of HSV-2 antibody positivity among Ds mothers, though not of sufficient magnitude to imply that HSV-2 can be the major cause of Ds. It is discussed whether HSV-2 might be related to the recently increased birthrate of children with Ds among young mothers in Sweden or to localized geographical clustering of Ds births, or whether the increased HSV-2 antibody positivity merely indicates that factors following the same epidemiological pattern are involved in the aetiology of Ds.

The ageing gamete in relation to birth control failures and Down syndrome

Some indirect relationships between contraception failures and offspring with a pathological condition are reviewed, and a causal connection between them is suggested. This hypothesis is supported by the decreasing incidence of Down syndrome (DS) in general in recent years, and the increase among the younger maternal age categories as well as the effect of birth order. A more than doubled incidence of DS children among young Catholic mothers and the fact that conceptions of children with DS are preceded by unusually long periods of abstinence are emphasised and discussed. These data offer circumstantial evidence that the conceptions that occur despite application of the so called "natural" family planning methods in particular are at high risk. The impact of reproductive biological failures ("nature") and of reproductive behaviour ("nurture") on the human gametes can be disentangled by thorough studies of the epidemiology of major and minor congenital anomalies.

Protracted survival in patients with Down's syndrome

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