Discordant expression of fetal hydantoin syndrome in heteropaternal dizygotic twins.
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Abnormalities, Drug-Induced↗
Biomedical subjects
M C Phelan
Publications and source records attributed to M C Phelan.
Determinants of ridge counts in MZ twin kinships.
The inheritance of total ridge count (TRC) was studied in 967 individuals from the families of 111 pairs of MZ twins. The sample included data on 47 male half-sibships with 227 offspring and 64 female half-sibships with 306 offspring. The males in this sample had a mean ridge count of 135 +/- 2 and the females a mean ridge count of 124 +/- 2. The distribution of scores for females showed evidence for significant skewness. For this reason, prior to the analysis, the data were corrected for sex and adjusted to normality using a power transformation. Nested analyses of variance were performed on the ridge counts from male and female half-sibships separately to derive estimates of among, between, and within-variance components. These estimates were then used in a nonlinear least squares program to estimate genetic and environmental parameters and to determine the goodness of fit of various models. A model which included additive genetic and dominance effects could not be rejected (P = 0.67) but did not fit the data as well as a simple additive genetic-random environmental model (P = 0.81). The addition of maternal effects to the later model also provided a satisfactory fit (P = 0.68). However, there were no improvement in the goodness of fit over the simple model, and estimated magnitude of the maternal effect was not significantly different from zero.
Analysis of Variance↗
New method for obtaining uncontaminated urine from women.
Midstream sampling and colony counts have greatly improved precision in diagnosing urinary tract infections. In women, however, contamination by vaginal flora and cells still poses a diagnostic problem. We have devised an instrument for helping collect uncontaminated urine from women and have tested it in three sets of observations. Approximately 96% of 200 women were able to use the device successfully after minimal instruction. Bacterial colony counts and quantitative estimation of vaginal epithelial cells were performed on urine collected by 18 female volunteers using conventional clean-catch technics and on urine collected by the same 18 women using the Clean Streamer. The average bacterial colony count in conventionally collected urine was 8,100/ml while in Clean Streamer collected urine it was 1,722/ml. The average number of vaginal epithelial cells in conventionally collected urine was 22.4/ml while in Clean Streamer collected urine it was 14.1/ml. The difference in both comparisons is statistically significant (P = .01). We believe that use of the Clean Streamer greatly facilitates the ability of a woman to collect a urine sample uncontaminated by vaginal secretions and flora.
Bacteriuria↗
Fragile X syndrome and neoplasia.
Among 100 males with fragile X [fra(X)] or Martin-Bell syndrome, two have developed malignancies. The first case, a 57-year-old man with fra(X) expression in 12% of peripheral blood lymphocytes, developed a seminoma of the left testis at age 45 years and in the right testis at age 50 years. The second case, a 16-year-old white boy with fra(X) expression in 23% of lymphocytes, developed a mucin-producing adenocarcinoma of the colon at age 14 years. Because of the unusual nature of the tumors observed in these patients and in 2 other patients from the literature, we suggest that individuals with the fra(X) syndrome may be at increased risk of cancer.
Adenocarcinoma, Mucinous↗
Fragile X syndrome: linkage analysis in black and white populations.
Eleven white families and 10 black families have been studied to detect racial differences in the linkage of DNA markers flanking the fragile X site (FRAXA). The differences in the recombination fractions for F9-FRAXA and DX13-FRAXA were not significant. The pair St14-FRAXA exhibited no difference between the two groups. Although the sample size was small, it would appear that these DNA markers can be used in black persons for prenatal diagnosis and genetic counseling. A larger group of families would be necessary to determine if 4D8 and cX55.7 will be equally useful since these appear to have lower heterozygote frequencies in the black population.
Black People↗
Fragile X syndrome: incidence, clinical and cytogenetic findings in the black and white populations of South Carolina.
Individuals in South Carolina with the Fragile X [fra(X)] or Martin-Bell syndrome have been ascertained by referral for evaluation of facial abnormalities, macroorchidism or mental deficit; by screening patients in residential and day programs for the mentally retarded; and by family follow up after an index case has been identified. Between 1982 and 1987, 100 positive fra(X) males were diagnosed. Of these, 35 were residents of residential facilities for the mentally retarded representing 2.5% of the population of institutionalized males. Another 23 were found in community day programs for the mentally retarded. Of these 58 cases, 28 (48%) were ascertained by screening for the craniofacial characteristics of the Martin-Bell syndrome, namely long face, midface hypoplasia, prominent forehead, large mandible and large simple pinnae. Although this screening procedure proved to be productive, it was found that the craniofacial traits of long face, midface hypoplasia, large jaw and simple pinnae were found less frequently in black fra(X) positive males and in prepubertal boys of both races.
Black People↗
Deletion of Huntington's disease-linked G8 (D4S10) locus in Wolf-Hirschhorn syndrome.
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by progressive involuntary movements and dementia. The symptoms of the disease, although devastating in severity, do not usually appear until the third to fourth decade of life. The gene defect is highly penetrant, and results in the loss of neurones in the basal ganglia, globus pallidus, and more diffusely in the cortex. A DNA marker, G8 (or D4S10), is tightly linked to Huntington's disease and this gene has been localized to chromosome 4 (ref. 3). The discovery of this linkage marker raises the possibility of developing a presymptomatic test for the disorder, and of eventually isolating the disease gene based on its map position. We have now regionally localized the DNA marker G8 to the terminal band of the short arm of the chromosome, a region representing approximately 0.5% of the total human genome. The assignment was made by examining DNA from patients with Wolf-Hirschhorn syndrome, a birth defect resulting from partial heterozygous deletion of the short arm of chromosome 4.
Abnormalities, Multiple↗