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Biomedical subjects

E B Hook

Publications and source records attributed to E B Hook.

At least 109 records · Page 6Linked to original sources
PubMed1987

Issues in analysis of data on paternal age and 47,+21: implications for genetic counseling for Down syndrome.

Data and analyses on paternal age and 47,+21 are reviewed. It is concluded that there are few, if any, grounds to justify the inference of a paternal age effect independent of maternal age for those paternal age-maternal age combinations on which there are prenatal diagnostic data. It is suggested that genetic counseling as to increased (or decreased) risk of Down syndrome associated with various paternal ages is not justified at present.

Adult↗
PubMed1987

An analysis of paternal age and 47,+21 in 35,000 new prenatal cytogenetic diagnosis data from the New York State Chromosome Registry: no significant effect.

In 35,680 fetuses of women who had prenatal cytogenetic diagnosis done upon amniotic fluid specimens obtained during 2nd trimester amniocentesis and in whom there was no increased cytogenetic risk except for age, there was no statistically significant evidence for an increase of 47,+21 at any paternal age after adjustment for maternal age. The ratio of observed-to-expected numbers in fathers less than 30 years old was 1.0 and in fathers 40 years or older was 0.9 when compared with numbers derived from maternal-age-specific rates in men 30-39 years old. The ratio was 1.1 for those younger than 34 years when compared with rates in fathers aged 34-39 years old. Only for men 55 years or older was there any, even suggestive, increase. The ratio was roughly 1.5 (9 observed to about 6 expected). This was not statistically significant, and moreover, the increase such as it was, was in men married to women 37-42 years old. Regression analyses using several additive parental age models introducing a parabolic function for paternal age, failed to reveal any paternal age contribution.

Adult↗
PubMed1987

Rates of mutant and inherited structural cytogenetic abnormalities detected at amniocentesis: results on about 63,000 fetuses.

We report data on diagnoses made on amniotic fluid specimens from 1977 to 1984 as reported to the New York State Chromosome Registry. The rate of all de novo (presumed mutant) abnormalities was about 2 per 1,000 in about 61,000 fetuses in which results are unlikely to be biased by the reason for amniocentesis (except for maternal age). This includes about 0.5 per 1,000 de novo markers, about 0.5 per 1,000 other de novo unbalanced, and about 1.0 per 1,000 de novo balanced rearrangements. In about 55,000 fetuses in which rates of inherited abnormalities could be evaluated without apparent bias, the rate of all inherited rearrangement was about 2.9 per 1,000. This includes about 0.3 per 1,000 inherited markers, about 0.2 per 1,000 other inherited unbalanced rearrangements, and about 2.4 per 1,000 inherited balanced abnormalities. Only mutant markers showed a clear association with maternal age (37.6 +/- 2.7 in 24 cases v. 35.8 +/- 3.6 in controls). Inherited markers did not exhibit this trend (35.8 +/- 2.0 in 12 cases v. 36.4 +/- 2.8 in controls). Paternal age does not appear to account for the association. Among abnormalities of known origin, the ratio of mutant to inherited cases is for markers 64:36, for other unbalanced rearrangements 73:27, and for all balanced abnormalities 29:71. In a subgroup of about 55,000 fetuses, of 263 total abnormalities there were 8 instances of apparent true somatic mosaics (5 mutant and 3 of unknown origin but almost certainly mutant). There were also 20 instances of markers in which presumptive somatic loss had resulted in mosaicism (10 mutant, 6 of unknown origin and 4 inherited) and 13 other instances of mosaicism associated with apparent somatic loss (9 mutant, 3 of unknown origin, and 1 inherited). The sex ratio (Y to non-Y karyotypes) for all abnormalities detected was 228:210 (1.09), not different from controls. Only deletions (5:14) and 'other' unbalanced rearrangements (5:13) exhibited a suggestive deviation from this trend. The rates of mutant chromosome rearrangements reported from 1977 to 1983 showed no apparent time cluster, with the possible exception of a peak of markers in 1977, a trend that may be due to higher maternal age in this year. Among fetuses studied because of maternal exposure to putative mutagens there was a non-significant excess of mutants (2.9-5.7 per 1,000 v. 1.7-2.2 per 1,000) and a borderline significant excess of inherited rearrangements (8.6-11.5 per 1,000 v. 2.6-3.1 per 1,000).(ABSTRACT TRUNCATED AT 400 WORDS)

Amniocentesis↗
PubMed1987

Extra structurally abnormal chromosomes (ESAC) detected at amniocentesis: frequency in approximately 75,000 prenatal cytogenetic diagnoses and associations with maternal and paternal age.

We analyzed rates of extra structurally abnormal chromosomes (ESAC) detected in prenatal cytogenetic diagnoses of amniotic fluid reported to the New York Chromosome Registry. These karyotypes include both extra unidentified structurally abnormal chromosomes (EUSAC)--often denoted as "markers"--and extra identified structurally abnormal chromosomes (EISAC). The rate of all EUSAC was 0.64/1,000 (0.32-0.40/1,000 mutant and 0.23-0.32 inherited), and that of all EISAC was 0.11/1,000 (0.07/1,000 mutant and 0.04/1,000 inherited). The rate of all ESAC was approximately 0.8/1,000-0.4-0.5/1,000 mutant and 0.3-0.4/1,000 inherited. Mean +/- SD maternal age of mutant cases was 37.5 +/- 2.9, significantly greater than the value of 35.8 years in controls. A regression analysis indicated a rate of change of the log of the rate of about +0.20 with each year of maternal age between 30 and 45 years. When paternal age was introduced, the maternal age coefficient increased to about +0.25--close to that seen for 47, +21--but the paternal age coefficient was -0.06. After being matched for maternal age and year of diagnosis, the case-control difference in paternal age for 24 mutant cases was -2.4 with a 95% confidence interval of -4.6 to -0.1 years. In a regression analysis of the effects of both parental ages on the (log) rate, the maternal age coefficient was +0.25 and the paternal age coefficient was -0.06. These results are consistent with a (weak) negative paternal age effect in the face of a strong maternal age effect. Since ESAC include a heterogeneous group of abnormalities, the maternal age and paternal age trends, if not the result of statistical fluctuation or undetected biases, may involve different types of events. Data in the literature suggest that chromosomes with de novo duplicated inversions of 15p have a strong maternal age effect (but little paternal age effect). Such chromosomes, however, do not account for the active maternal age trends seen in the data analyzed here. Inherited ESAC exhibited no such trends.

Adolescent↗
PubMed1986

Nausea and vomiting of pregnancy and association with pregnancy outcome.

The pattern of nausea and/or vomiting of pregnancy were investigated in a group of 414 predominantly white, upper middle-class women in Albany, New York; patterns were ascertained before their eighty-eighth day of gestation and followed up to the end of pregnancy. Of these, 89.4% reported at least some symptoms. This frequency is higher than reported previously, perhaps in part because extensive attempts were made in this study to ascertain symptoms. The incidence of vomiting was about 55%. Women with no symptoms of nausea and/or vomiting of pregnancy experienced a significantly greater proportion of nonviable pregnancy outcomes (fetal death). Increased intake of niacin during the first trimester was associated with decreased infant birth weight. This may be the result of quicker fetal maturation due to increased levels of protein intake.

Female↗
PubMed1985

False-positive reporting of Down syndrome on Ohio and New York birth certificates.

Although correction for underreporting of congenital malformations on birth certificates is included in most studies, inaccuracy of reporting has not been widely examined. Two separate investigations were conducted on the inaccuracy of Down syndrome (DS) reporting on birth certificates; ie, false-positive cases in which an individual coded as DS did not in fact have DS. In Ohio, 824 individuals were coded as DS on their birth certificate during 1970-1981. Of these, a definitive determination as to whether or not they had DS was made on 778 by using cytogenetic data, medical records, the state's birth defects registry, school records, and by questioning physicians. Fifty-seven false-positives were found, indicating a 7.8% level of coding inaccuracy for all races and 6.9% for whites only. Nine of these arose from miscodings during data processing; 48 were misdiagnosed as DS. This can be contrasted with false-negatives also studied in Ohio, where 66.1% of DS cases were not reported on the birth certificate. No statistical differences were observed between false-positives and true DS in the distribution of sexes, in population size of county of birth, or in year of birth (although there was a declining false-positive rate over the 12 year period). The percentage of DS false-positives, however, was significantly higher for younger maternal ages (greater than or equal to 30 years) than older ones (greater than or equal to 30 years) and for nonwhites compared to whites. Further, there was a strong negative correlation between the percentage of false-positives and the degree of certainty expressed in reporting DS on the birth certificate.

Adolescent↗
PubMed1985

Cigarette smoking and Down syndrome.

A matched case-control study of 100 mothers of Down syndrome children, 100 mothers of children with other defects (defect controls), and 100 mothers of children with no defects (normal controls) was carried out. All infants were born in upstate New York in 1980 and 1981. Matching was very close on maternal age for the normal controls but not for the defect controls. The risk ratios for the association of cigarette smoking around the time of conception with Down syndrome was 0.58 (90% confidence interval of 0.34-0.98) in the case-defect control comparison and 0.56 (90% confidence interval of 0.33-0.95) in the case-normal control comparison. Stratification by alcohol ingestion and maternal age did not abolish the negative trend to association. The results are contrary to that of an earlier study of others that found a positive association of older age and trisomy in spontaneous abortions. In fact, among mothers of Down syndrome cases over age 30 in this analysis, the risk ratio was lower than for younger mothers. (For case-normal control comparisons, the value was 0.39 [90% confidence interval of 0.17-0.87]). If not due to chance or confounding, the negative association in our data may be attributable to, among other factors, a selective effect of smoking upon survival or fertilizability of +21 gametes prior to conception or upon survival of +21 conceptuses after fertilization.

Congenital Abnormalities↗