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Biomedical subjects

W T Brown

Publications and source records attributed to W T Brown.

At least 163 records · Page 9Linked to original sources
PubMed1983

Monosomy 21 syndrome: further delineation including clinical, neuropathological, cytogenetic and biochemical studies.

Only six cases of living newborns with apparently complete monosomy 21 have been reported. All the previous cases with the exception of the present case died between 3 weeks and 20 months. Only one of these cases had a postmortem examination. The subject of this report was previously described at the age of 6 years (Davis et al. 1976). He survived until 11 years old and is the oldest known case of complete monosomy 21. We report here the clinical presentation over 11 years, results of gene dosage studies, cytogenetic analysis, and the neuropathological postmortem examination.

Aneuploidy↗
PubMed1983

The strength of association between fragile (X) chromosome presence and mental retardation.

In order to obtain a quantitative estimate of the degree of association between presence of fragile X chromosome (fra(X] and mental retardation (MR), existing data from nonretarded males were analyzed. Clearly, fra(X) occurs less frequently among nonretarded compared to MR males. However, incidence estimates for fra(X) based upon existing data hold open the possibility that there may be significant numbers of nonretarded males with fra(X). Additional analyses of data from families with a pattern of fra(X) linked MR showed: (a) the probability that nonretarded male offspring will have fra(X) is very small, and (b) the probability that MR male offspring will have fra(X) is very large. Thus, accurate prognostic decisions can be based upon prenatal diagnosis of fra(X) presence, especially in families with a pattern of fra(X) linked MR.

Female↗
PubMed1983

Atypical Down syndrome and partial trisomy 21.

A case of "atypical" Down Syndrome (DS), where the proposita did not exhibit all of the clinical features of DS and had de novo partial trisomy 21, was studied. Results from phenotypic, chromosome banding and superoxide dismutase (SOD) gene dosage studies suggest a karyotype of 46,XX,-12,+t(12pter to 12qter::21q21 to 21q22.?2). Additional studies of such atypical cases will provide more precise sublocalization for both gene and phenotypic mapping of the bands that are responsible for the DS phenotype.

Child↗
PubMed1982

Association of mitral-valve prolapse with low body-weight and low blood pressure.

Subjects with mitral-valve prolapse (MVP) have been observed to have an asthenic body build. To determine whether body-weight differed between individuals with inherited MVP and normal subjects, 177 relatives of 45 patients with MVP were studied, 35 female and 19 male relatives had MVP, and 51 female and 72 male relatives did not. There was no difference in mean height between relatives with and without MVP, but those with MVP weighed significantly less. Blood pressure was also significantly lower in relatives with MVP than in normal relatives. It is suggested that the lower blood pressure and the possible beneficial effects of lower weight on other cardiovascular risk factors may provide a selective advantage to carriers of the MVP gene, explaining its high prevalence in the general population. These findings may provide the first example of a common inherited condition which is systematically associated with changes in body-weight and blood pressure.

Adolescent↗
PubMed1982

Inheritance of mitral valve prolapse: effect of age and sex on gene expression.

To ascertain if mitral valve prolapse is inherited we studied 45 probands and 179 first-degree relatives. Echocardiographic mitral prolapse was present in 54 of 179 first-degree relatives (30%); at least one first-degree relative was affected in 29 families, including members of two generations in 23 families. The number of affected persons in the 54 sibships fell within the range predicted for autosomal dominant inheritance. The familial prevalence of prolapse was similar whether or not the proband had characteristic symptoms, auscultatory abnormalities, electrocardiographic findings, thoracic bony abnormalities, or coexistent heart disease. Mitral prolapse occurred in 37 of 90 women (41%) but 17 of 89 men (19%; p less than 0.005), and in 51 of 143 adults (35%) but only 3 of 36 children aged 1 to 15 (p less than 0.005). Mitral valve prolapse is an inherited autosomal dominant condition irrespective of clinical findings, and the mitral prolapse gene shows age and sex dependent expression. Mitral valve prolapse appears to be the commonest mendelian cardiovascular abnormality in humans.

Adolescent↗
PubMed1982

Alpha 1-antitrypsin: apparent molecular weight heterogeneity shown by two-dimensional electrophoresis.

Two-dimensional (2-D) gel electrophoresis was used to examine charge and molecular weight variability of alpha 1-antitrypsin. Two-D electrophoresis resolved distinctive differences among individual phenotypes. Microheterogeneity of charge was seen for the different alleles that corresponded to the charge variability observed on isoelectric focusing gels. The molecular weights of the major components of each allele appeared to differ from each other by approximately 1,000, suggesting, that in addition to sialic acid, there may be differences in neutral sugar composition between the individual components. In comparison to the M allele components, the corresponding S and Z components had higher molecular weights. The MZ and MS phenotypes showed characteristic patterns of protein spot doublets. Computerized quantitation was used to separate and estimate the contribution of each component to the overall allele composition. The Z allele components contained about 15% of the total MZ quantity. The 2-D electrophoresis technique may offer a new approach for molecular structural studies of alpha 1-antitrypsin variants and similar glycoproteins.

Alleles↗