Jennie Kline

De novo mutations in histone-modifying genes in congenital heart disease.

Congenital heart disease (CHD) is the most frequent birth defect, affecting 0.8% of live births. Many cases occur sporadically and impair reproductive fitness, suggesting a role for de novo mutations. Here we compare the incidence of de novo mutations in 362 severe CHD cases and 264 controls by analysing exome sequencing of parent–offspring trios. CHD cases show a significant excess of protein-altering de novo mutations in genes expressed in the developing heart, with an odds ratio of 7.5 for damaging (premature termination, frameshift, splice site) mutations. Similar odds ratios are seen across the main classes of severe CHD. We find a marked excess of de novo mutations in genes involved in the production, removal or reading of histone 3 lysine 4 (H3K4) methylation, or ubiquitination of H2BK120, which is required for H3K4 methylation. There are also two de novo mutations in SMAD2, which regulates H3K27 methylation in the embryonic left–right organizer. The combination of both activating (H3K4 methylation) and inactivating (H3K27 methylation) chromatin marks characterizes ‘poised’ promoters and enhancers, which regulate expression of key developmental genes. These findings implicate de novo point mutations in several hundreds of genes that collectively contribute to approximately 10% of severe CHD.

DRINKING DURING PREGNANCY AND SPONTANEOUS ABORTION

The frequency of drinking alcohol among 616 women who aborted spontaneously (cases) was compared with that among 632 women who delivered after at least 28 weeks gestation (controls). 17.0% of cases reported drinking twice a week or more during pregnancy whereas among controls, only 8.1% of women reported drinking twice a week or more. The hypothesis that drinking during pregnancy is associated with spontaneous abortion was tested by maximum-likelihood logistic regression analysis. The adjusted-odds ratio for this association was 2.62. We estimate that more than 1/4 of pregnant women drinking twice a week or more are likely to abort, compared with about 14% among women who drink less often. Consideration of wine, beer, and spirits suggested that the minimum harmful dosage was 1 ounce of absolute alcohol. Several potentially confounding variables, including maternal age, gestation, prior spontaneous abortions, smoking, and nausea/vomiting, were controlled in the analysis. The association between drinking during pregnancy and spontaneous abortion did not vary with these factors. Even moderate alcohol consumption during pregnancy is a risk factor for, and may be a cause of, spontaneous abortion. Among the possible mechanisms, acute fetal poisoning seems the most likely, although chronic poisoning is also possible.

Water arsenic exposure and intellectual function in 6-year-old children in Araihazar, Bangladesh.

Background We recently reported results of a cross-sectional investigation of intellectual function in 10-year-olds in Bangladesh, who had been exposed to arsenic from drinking water in their home wells. Objectives We present results of a similar investigation of 301 randomly selected 6-year-olds whose parents participated in our ongoing prospective study of the health effects of As exposure in 12,000 residents of Araihazar, Bangladesh. Methods Water As and manganese concentrations of tube wells at each home were obtained by surveying all study region wells. Children and mothers were first visited at home, where the quality of home stimulation was measured, and then seen in our field clinic, where children received a medical examination wherein weight, height, and head circumference were assessed. We assessed children’s intellectual function using subtests drawn from the Wechsler Preschool and Primary Scale of Intelligence, version III, by summing weighted items across domains to create Verbal, Performance, Processing Speed, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and were asked to provide blood samples for blood lead measurements. Results Exposure to As from drinking water was associated with reduced intellectual function before and after adjusting for water Mn, for blood lead levels, and for sociodemographic features known to contribute to intellectual function. With covariate adjustment, water As remained significantly negatively associated with both Performance and Processing Speed raw scores; associations were less strong than in our previously studied 10-year-olds. Conclusion This second cross-sectional study of As exposure expands our concerns about As neurotoxicity to a younger age group.

Arsenic and manganese exposure and children's intellectual function

Recently, epidemiologic studies of developmental neurotoxicology have been challenged to increase focus on co-exposure to multiple toxicants. Earlier reports, including our own work in Bangladesh, have demonstrated independent associations between neurobehavioral function and exposure to both arsenic (As) and manganese (Mn) in school-aged children. Our earlier studies, however, were not designed to examine possible interactive effects of exposure to both As and Mn. To allow investigation of possible synergistic impact of simultaneous exposures, we recruited a new sample of 299 8-11 year old children, stratified by design on As (above and below 10 μg/L) and Mn (above and below 500 μg/L) concentrations of household wells. When adjusted only for each other, both As and Mn in whole blood (BAs; BMn) were significantly negatively related to most WISC-IV subscale scores. With further adjustment for socio-demographic features and ferritin, BMn remained significantly associated with reduced Perceptual Reasoning and Working Memory scores; associations for BAs, and for other subscales, were expectably negative, significantly for Verbal Comprehension. Urinary As (per gram creatinine) was significantly negatively associated with Verbal Comprehension scores, even with adjustment for BMn and other contributors. Mn by As interactions were not significant in adjusted or unadjusted models (all ps>0.25). Findings are consistent with other reports documenting adverse impact of both As and Mn exposure on child developmental outcomes, although associations appear muted at these relatively low exposure levels.

Age and the ovarian follicle pool assessed with transvaginal ultrasonography

OBJECTIVE We tested whether transvaginal ultrasonography could detect the age-related decrease in follicle counts that has been observed in autopsy studies. STUDY DESIGN Thirty-one healthy volunteers in three age groups (22 to 25, 30 to 33, and 39 to 42 years) underwent ultrasonography in the follicular and luteal phases of the menstrual cycle. At the conclusion of the study the 124 ovarian scans were randomly ordered and antral follicles > or = 2 mm were counted by an evaluator unaware of age. Ordinary least-squares linear regression was used to estimate the associations of age with the total antral follicle count and with ln (1 + follicle count). RESULTS The numbers of antral follicles > or = 2 mm decreased by about 60% between 22 and 42 years. Age-related decreases were similar for both phases of the cycle and held for both smaller (2 to 3.5 mm) and larger (>3.5 mm) follicles. CONCLUSION We hypothesize that ultrasonographically derived counts of follicles provide a measure of reproductive age that may help to predict age-related phenomena.

Depressive symptoms in women in the six months after miscarriage

This study, the first systematic investigation of the psychiatric impact of miscarriage, tests whether miscarriage markedly increases depressive symptoms in the 6 months after loss. We interviewed 382 miscarrying women entering the study at 2 weeks, 6 weeks, or 6 months after loss and, for comparison, 283 pregnant women and 318 community women not recently pregnant. Among women interviewed 2 weeks after miscarriage the proportion highly symptomatic on the Center for Epidemiologic Studies-Depression scale was 3.4 times that of pregnant women (95% confidence limits 2.0 and 5.0) and 4.3 times that of community women (95% confidence limits 3.0 and 5.8). Among women first interviewed 6 weeks and 6 months after miscarriage the proportion highly symptomatic was three times that of the community women. Women reinterviewed at 6 weeks and 6 months did not have elevated symptom levels, a result attributed to the unintended therapeutic and test effects of study interviews. Interviews were fully structured, readily administered by telephone by nonmedical personnel. The possibility that such interviews afford miscarrying women substantial psychologic benefits merits future investigation.

Trisomy Recurrence: A Reconsideration Based on North American Data

Few reliable data exist concerning the recurrence risk for individual trisomies or the risk for recurrence of trisomy for a different chromosome. We collected records from two sources: (1) prenatal diagnoses performed at the Hopital Sainte-Justine in Montreal and (2) karyotype analyses performed at Genzyme. Using the standardized morbidity ratio (SMR), we compared the observed number of trisomies at prenatal diagnosis with the expected numbers, given maternal age-specific rates (by single year). SMRs were calculated both for recurrence of the same trisomy (homotrisomy) and of a different trisomy (heterotrisomy). After all cases with an index trisomy 21 were combined, the SMR for homotrisomy was 2.4 (90% CI 1.6-3.4; P=.0005). For women with both the index trisomy and subsequent prenatal diagnosis at age <30 years, the SMR was 8.0; it was 2.1 for women with both pregnancies at age >/=30 years. For the other index viable trisomies (13, 18, XXX, and XXY) combined, the SMR for homotrisomy was 2.5 (90% CI 0.7-8.0). For heterotrisomy, the SMR after an index trisomy 21 was 2.3 (90% CI 1.5-3.8, P=.0007); the SMR did not vary with maternal age at the first trisomy. When all cases with index viable trisomies were combined, the SMR for heterotrisomy was 1.6 (90% CI 1.1-2.4; P=.04). For prenatal diagnoses following a nonviable trisomy diagnosed in a spontaneous abortion (from Genzyme data only), the SMR for a viable trisomy was 1.8 (90% CI 1.1-3.0; P=.04). The significantly increased risk for heterotrisomy supports the hypothesis that some women have a risk for nondisjunction higher than do others of the same age.

The Yugoslavia Prospective Lead Study: contributions of prenatal and postnatal lead exposure to early intelligence

To investigate associations between the timing of lead (Pb) exposure on early intelligence, we examined the results of psychometric evaluations at ages 3, 4, 5, and 7 years, from 442 children whose mothers were recruited during pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia. We compared the relative contribution of prenatal blood lead (BPb) with that of relative increases in BPb in either the early (0-2 years) or the later (from 2 years on) postnatal period to child intelligence measured longitudinally at ages 3 and 4 (McCarthy GCI), 5 (Wechsler Preschool and Primary Scale of Intelligence-Revised, WPPSI-R IQ), and 7 (Wechsler Intelligence Scale for Children-version III, WISC-III IQ), controlling for: Home Observation for Measurement of the Environment (HOME) quality; maternal age, intelligence, education, and ethnicity; and birthweight and gender. Elevations in both prenatal and postnatal BPb were associated with small decrements in young childrens intelligence.

Independent effects of lead exposure and iron deficiency anemia on developmental outcome at age 2 years

For a prospective study of lead exposure, iron status, and infant development, we recruited infants living in a smelter town and a non-lead-exposed town in Kosovo, Yugoslavia. Among 392 infants assessed at age 2 years, the mean Mental Development Index (MDI), Bayley Scales of Infant Development, was 105.2. At age 2 years, geometric mean blood lead concentrations were 35.5 and 8.4 micrograms/dl, respectively, among infants from the exposed and nonexposed towns. After controlling for variables associated with MDI, we found significant independent associations for both blood lead and hemoglobin concentrations. For example, a rise in blood lead concentration at age 2 years from 10 to 30 micrograms/dl was associated with an estimated 2.5 point decrement in MDI (p = 0.03); statistically nonsignificant decrements were associated with blood lead levels measured at birth and at 6, 12, and 18 months of age. A decrease in hemoglobin concentration at 18 months of age from 12 to 10 gm/dl was associated with an estimated 3.4 point decrement in MDI (p = 0.02); the latter association was present in both towns, suggesting that it was due to iron deficiency anemia independent of lead exposure. The findings suggest that the brain is vulnerable to the effects of both lead exposure and anemia before 2 years of age. On a global basis, the developmental consequences of anemia may exceed those of lead exposure.

Determinants of depressive symptoms in the early weeks after miscarriage.

OBJECTIVES We tested whether and under what conditions miscarriage increases depressive symptoms in the early weeks following loss. METHODS We interviewed 232 women within 4 weeks of miscarriage and 283 pregnant women and 318 community women who had not recently been pregnant. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression (CES-D) Scale. RESULTS Among women who had miscarried, the proportion who were highly symptomatic on the CES-D was 3.4 times that of pregnant women and 4.3 times that of community women. Among childless women, the proportion of women who had miscarried who were highly symptomatic was 5.7 times that of pregnant women and 11.0 times that of community women. Women who had miscarried were equally depressed regardless of length of gestation; among pregnant women, depressive symptoms declined with length of gestation. Among women who had miscarried, symptom levels did not vary with attitude toward the pregnancy; among pregnant women, depressive symptoms were elevated in those with unwanted pregnancies. Prior reproductive loss and advanced maternal age (35+ years) were not associated with symptom levels in any cohort. CONCLUSIONS Depressive symptoms are markedly increased in the early weeks following miscarriage. This effect is substantially modified by number of living children, length of gestation at loss, and attitude toward pregnancy.