Descriptive epidemiology of nonsyndromic omphalocele in Texas, 1999-2004

Omphalocele is a congenital malformation that involves protrusion of abdominal contents into the umbilicus. Though omphalocele may present as a manifestation of several chromosomal and Mendelian syndromes, the etiology for nonsyndromic omphalocele is unknown. The present study sought to estimate the birth prevalence of nonsyndromic omphalocele in offspring of women residing in Texas from 1999 to 2004, and to describe prevalence as a function of parental and infant demographic characteristics. Data on 325 cases with nonsyndromic omphalocele and 2,208,758 live births delivered during 1999-2004 were obtained from the Texas Birth Defects Registry. These data were used to estimate omphalocele birth prevalence and obtain both crude and adjusted prevalence ratios for the association of nonsyndromic omphalocele with parental and infant demographic characteristics. Nonsyndromic omphaloceles were significantly more common among the offspring of women without previous live births (adjusted prevalence ratio: 1.80, 95% CI: 1.41-2.30), compared to the offspring of women with previous live births. The prevalence of nonsyndromic omphalocele was also increased among women aged 25-29 (adjusted prevalence ratio: 1.68, 95% CI: 1.12-2.50) and women aged 40 and older (adjusted prevalence ratio: 4.83, 95% CI: 2.63-8.86) compared to the offspring of women age <20, and in infants of multiple gestation pregnancies compared to singleton infants (adjusted prevalence ratio: 2.03, 95% CI: 1.22-3.37). In addition, among Hispanic women, the prevalence of nonsyndromic omphalocele was higher in the offspring of those born in the U.S. as compared to those born elsewhere (adjusted prevalence ratio: 1.50, 95% CI: 1.12-2.00). These findings augment the existing omphalocele literature.

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

Prevalence of hypotensive disorders in older patients with a pacemaker in situ who attend the Accident and Emergency Department because of falls or syncope

AIMS

To ascertain the proportion of adults with a pacemaker in situ attending the Accident and Emergency Department because of syncope or unexplained falls and the cause of index symptoms in these patients, including the prevalence of hypotensive syndromes.

METHODS AND RESULTS

Patients presenting to the Accident and Emergency Department with unexplained syncope or non-accidental falls, who had a pacemaker in situ, were studied. Eligible patients had cardiovascular assessment (morning orthostatic blood pressure measurement, heart rate and BP measurements during carotid sinus stimulation (supine and upright), head-up tilt at 70 degrees for 40 min), assessment of haemodynamics during fixed mode pacing and gait and balance assessment. Of 5863 patients screened, 13.5% had unexplained syncope or a non-accidental fall; of these only 3% (26 patients) had pacemakers in situ. Of 18 study patients (82 +/- 8 years), 10 were female. Sixteen had a hypotensive diagnosis. Seven had more than one attributable hypotensive diagnosis. Five of 13 with vasodepressor carotid sinus syndrome had no previous diagnosis of carotid sinus hypersensitivity. No patients had vasovagal syncope induced during passive head-up tilt testing.

CONCLUSION

It is rare for patients who attend the Accident and Emergency Department because of syncope or unexplained falls to have a pacemaker in situ. In those who do, hypotensive disorders are a common finding.

Evaluation of two putative susceptibility loci for oral clefts in the Danish population

Previous studies suggest that the risk of nonsyndromic cleft lip with or without cleft palate (CL+/-P) and isolated cleft palate (CP) is influenced by genetic variation at several loci and that the relation between specific genetic variants and disease risk may be modified by environmental factors. The present study evaluated potential associations between CL+/-P and CP and two putative clefting susceptibility loci, MSX1 and TGFB3, using data from a nationwide case-control study conducted in Denmark from 1991 to 1994. The potential effects of interactions between these genes and two common environmental exposures, first trimester exposure to maternal cigarette smoke and alcohol intake, were also examined. Analyses of these data provide evidence of an association between the risk of CP and variation at the TGFB3 locus. However, there is no evidence that the risk of CL+/-P or CP is influenced by gene-environment interactions involving MSX1 or TGFB3 and either first trimester exposure to maternal cigarette smoke or alcohol consumption.

Relationship between case-control studies and the transmission/disequilibrium test

Case-control studies provide a powerful approach for detecting disease susceptibility loci that have only a weak to moderate impact on the risk of disease, or markers that are in linkage disequilibrium with such loci. However, since any association detected in a case-control study may result from uncontrolled confounding, evidence for disease-marker associations obtained from such studies must be confirmed by alternative methods. Since studies that use the transmission/disequilibrium test or TDT are frequently employed to confirm disease-marker associations detected in case-control studies, data are increasingly available from both case-control studies and "TDT studies" of the same disease-marker association. It would, therefore, be useful to have a single measure of the magnitude of the disease-marker association that would allow for comparison of results from these two study designs. Such a measure could also be used to estimate minimum sample size requirements for TDT studies of previously reported disease-marker associations. An obvious measure of the disease-marker association in TDT studies is the frequency (T) with which heterozygous parents transmit the putative, high-risk marker allele to affected offspring. In this paper, it is shown that T can also be estimated from case-control data with a minimum of assumptions, and that T is the critical parameter for determining power and estimating sample sizes for the TDT.

Transforming growth factor alpha locus and nonsyndromic cleft lip with or without cleft palate: a reappraisal

An association between nonsyndromic cleft lip with or without cleft palate (CL +/- P) and genetic variation at the transforming growth factor alpha (TGFA) locus was originally reported in 1989. Subsequent population-based studies of this association have provided conflicting results. The present analyses were undertaken to determine if the cumulative weight of the available data convincingly supports or refutes this association. The published data were analyzed for differences in allele frequencies between Caucasian CL +/- P patients (i.e., cases) and controls, and for heterogeneity between Caucasian samples. When all data except the original report were considered, there was a statistically significant association between TGFA and CL +/- P (M.H.O.R. = 1.43; 95% C.I. 1.12-1.80). However, there was evidence of significant heterogeneity in the TGFA allele frequencies between cases, but not controls, from different studies. The data suggest that the observed heterogeneity is unlikely to be attributable to differences in the ethnic composition of the cases among the various studies but may reflect differences in the proportion of cases with bilateral lip defects and/or with positive family histories of CL +/- P. Definitive conclusions regarding the source(s) of the observed heterogeneity could not, however, be drawn on the basis of the available data. Hence, at present, the evidence regarding an association between genetic variation at the TGFA locus and CL +/- P remains inconclusive.

Genetic influences on premature parturition in an Australian twin sample

We investigated possible genetic influences on women's liability to preterm birth, using data from a large sample of Australian female twin pairs. In a 1988-90 questionnaire survey, both members of 905 parous twin pairs (579 monozygotic and 326 dizygotic) reported on whether deliveries had been more than two weeks preterm. Tetrachoric twin pair correlations for first birth were rMZ = 0.20+/-0.11 and rDZ = -0.03+/-0.14, and for any birth were rMZ = 0.30+/-0.08 and rDZ = 0.03+/-0.11. Best-fitting models to data contained only additive genetic influences and individual environmental effects. Heritability was 17% for preterm delivery in first pregnancy, and 27% for preterm delivery in any pregnancy. In the former case, however, we could not reject a model without genetic influences. Although our data did not allow for differentiation of the varying aetiologies of premature parturition, results from this exploratory analysis suggest that further investigation of genetic influences on specific reasons for preterm birth is warranted.

PCR assay for screening patients at risk for 22q11.2 deletion

Deletions of 22q11.2 have been detected in the majority of patients with DiGeorge, velocardiofacial, and conotruncal anomaly face syndromes by either cytogenetic analysis, fluorescence in situ hybridization (FISH), or Southern blot hybridization. However, these techniques may not be the most efficient or cost-effective means of screening large numbers of "at-risk" patients. Therefore, we developed a PCR assay to assess a patient's likelihood of having a 22q11.2 deletion based on homozygosity at consecutive markers in the DiGeorge chromosomal region. The sensitivity and specificity of PCR screening were evaluated in a cohort of cardiac patients. We conclude that a PCR-based assay is a reliable and efficient means of identifying which patients are at greatest risk for a 22q11.2 deletion and should have FISH studies to confirm their deletion status.

Frequency of 22q11 deletions in patients with conotruncal defects

OBJECTIVES

This study was designed to determine the frequency of 22q11 deletions in a large, prospectively ascertained sample of patients with conotruncal defects and to evaluate the deletion frequency when additional cardiac findings are also considered.

BACKGROUND

Chromosome 22q11 deletions are present in the majority of patients with DiGeorge, velocardiofacial and conotruncal anomaly face syndromes in which conotruncal defects are a cardinal feature. Previous studies suggest that a substantial number of patients with congenital heart disease have a 22q11 deletion.

METHODS

Two hundred fifty-one patients with conotruncal defects were prospectively enrolled into the study and screened for the presence of a 22q11 deletion.

RESULTS

Deletions were found in 50.0% with interrupted aortic arch (IAA), 34.5% of patients with truncus arteriosus (TA), and 15.9% with tetralogy of Fallot (TOF). Two of 6 patients with a posterior malalignment type ventricular septal defect (PMVSD) and only 1 of 20 patients with double outlet right ventricle were found to have a 22q11 deletion. None of the 45 patients with transposition of the great arteries had a deletion. The frequency of 22q11 deletions was higher in patients with anomalies of the pulmonary arteries, aortic arch or its major branches as compared to patients with a normal left aortic arch regardless of intracardiac anatomy.

CONCLUSIONS

A substantial proportion of patients with IAA, TA, TOF and PMVSD have a deletion of chromosome 22q11. Deletions are more common in patients with aortic arch or vessel anomalies. These results begin to define guidelines for deletion screening of patients with conotruncal defects.

Genetic epidemiology of birth defects: nonsyndromic cleft lip and neural tube defects

This review has focused on only two common structural malformations. However, the difficulties and successes encountered while attempting to elucidate the genetic contribution to these two conditions are likely to be echoed in studies of other complex congenital anomalies. As our understanding of the mechanisms which give rise to a particular malformation gradually unfolds, the importance of a multidisciplinary approach to understanding the genetic contribution to these conditions becomes increasingly apparent. Experience indicates that both traditional and genetic epidemiologic approaches will be integral components of any such efforts, since the identification of environmental risk factors (e.g., folic acid) may provide clues regarding the nature of disease susceptibility loci, and the identification of susceptibility loci will provide new opportunities to explore potential environmental covariates of disease risk (e.g., maternal cigarette smoke). Although we are not yet in a position to completely describe the genetic contribution to any single structural malformation, advances over the past decade have led to a rapid increase in our ability to elucidate the relevant genetic factors. Given the complex nature of the nonsyndromic structural malformations, there is undoubtedly much work to be done before we fully understand the genetic contribution to even a single malformation. However, for the first time, such an understanding and the accompanying potential for prevention seem within our reach.

Genetic effects on variation in red-blood-cell folate in adults: implications for the familial aggregation of neural tube defects

Recent studies have implicated folic acid as an important determinant of normal human growth, development, and function. Insufficient folate levels appear to be a risk factor for neural tube defects (NTD), as well as for several chronic diseases of adulthood. However, relatively little is known about the factors that influence folate status in the general population. To estimate the relative contribution of genetic and nongenetic factors to variation in folate, we have evaluated red blood cell (RBC) folate levels in 440 pairs of MZ twins and in 331 pairs of DZ twins. The data were best described by a model in which 46% of the variance in RBC folate was attributable to additive genetic effects, 16% of the variance was due to measured phenotypic covariates, and 38% of the variance was due to random environmental effects. Moreover, the correlations for RBC folate in MZ co-twins (r = .46) and in repeat measures from the same individual (r = .51) were very similar, indicating that virtually all repeatable variation in RBC folate is attributable to genetic factors. On the basis of these results, it would seem reasonable to initiate a search for the specific genes that influence RBC folate levels in the general population. Such genes ultimately may be used to identify individuals at increased risk for NTD and other folate-related diseases.

Observations on a recent increase in plagiocephaly without synostosis

OBJECTIVE

To verify and determine the cause of an increase in the referral of infants with plagiocephaly without synostosis (PWS) to a single tertiary craniofacial center.

DESIGN

A chart review was performed for 269 infants with a diagnosis of PWS who presented to a single tertiary craniofacial center between 1979 and 1994. The pattern of referral for PWS was analyzed using both simple linear regression and time series regression analyses. In addition, the referral pattern for PWS was compared with that for infants seen at the same center who received a diagnosis of synostotic plagiocephaly. Changes in the distribution of several demographic, perinatal, and clinical variables during the study period were also assessed. Finally, in an effort to identify correlates of the risk of PWS developing, characteristics of patients who were Missouri residents and presented between 1992 and 1994 were evaluated and compared with those of the 1993 Missouri live birth cohort.

SETTING

The Cleft Palate and Craniofacial Deformities Institute, St Louis Children's Hospital, Washington University Medical Center.

RESULTS

The average annual number of referrals to our center for PWS in the period 1992 to 1994 was more than sixfold greater than that for the preceding 13 years. There was a statistically significant increase in the annual number of referrals to our center during the 16-year study period. Moreover, there was evidence that the average annual increase in referrals was significantly greater during the last 3 years (1992 through 1994) of the study than in the first 13 years. This shift in the referral patterns is roughly contemporaneous with the American Academy of Pediatrics recommendations regarding infant sleep position. There was no evidence that either the mean number of referrals or the average annual increase in referrals for patients with synostosis changed during the study period. Among patients with PWS, the average age at presentation did not change during the study period. There were also no significant changes in the distribution of other demographic, perinatal, and clinical variables. When compared with the Missouri birth cohort, infants with PWS were significantly more likely to be boys and to have been delivered by forceps. There was also some evidence that patients with PWS were more likely to be born prematurely and to be products of multiple-gestation pregnancies. These associations were, however, of only borderline statistical significance.

CONCLUSION

Referrals to our center for PWS increased markedly in 1992 relative to previous years. The temporal coincidence of this increase with the American Academy of Pediatrics recommendation to avoid the prone sleeping position, to reduce the risk of sudden infant death syndrome, suggests a possible causal relationship. If this association is causal, education regarding the need for head position rotation coupled with that for sudden infant death syndrome should obviate positional PWS.

Analysis of the recurrence patterns for nonsyndromic cleft lip with or without cleft palate in the families of 3,073 Danish probands

The identification of several putative susceptibility loci for nonsyndromic cleft lip with or without cleft palate (CL +/- P) has sparked a renewed interest in the genetics of this condition. However, prior to undertaking linkage studies for complex traits such as CL +/- P it is desirable to have some understanding of the number and nature of the loci involved in disease susceptibility. The ability to obtain valid estimates of these parameters is contingent on the availability of family data which are unbiased by factors that distort the true familial recurrence pattern. In an effort to obtain such data, 2 centralized data repositories (the Danish Central Person Registry and the Danish Facial Cleft Database), were linked and used to estimate the risks to first, second, and third-degree relatives of 3,073 CL +/- P probands born in Denmark from 1952 to 1987. Analyses of these data excluded single locus and additive multilocus inheritance of CL +/- P, and provided evidence that CL +/- P is most likely determined by the effects of multiple interacting loci. Under a multiplicative model, no single locus can account for more than a threefold increase in the risk to first-degree relatives of CL +/- P probands. These data provide further evidence that nonparametric linkage methods (ex. affected relative pair studies) are likely to represent a more realistic approach for identifying CL +/- P susceptibility loci, than are traditional pedigree-based methods. However, at least 100 and more realistically several hundred (300-500) affected sib pairs are likely to be required to detect linkage to CL +/- P susceptibility loci.

Familial recurrence-pattern analysis of nonsyndromic isolated cleft palate--a Danish Registry study

The finding of an association between genetic variation at the transforming growth-factor alpha (TGFA) locus and nonsyndromic isolated cleft palate (CP) represents a potentially important breakthrough in our understanding of this condition. The present study was undertaken to assess the feasibility of detecting linkage to putative CP-susceptibility loci, such as TGFA. To this end, the familial recurrence pattern for CP was evaluated to determine the most likely mode of inheritance for this condition. The study took advantage of the high ascertainment and uniform registration of CP in Denmark. In addition, the study utilized estimates of familial recurrence that were obtained by register linkage and, hence, were not subject to either recall bias or the potentially biasing influence of nonresponders. The recurrence risks for first-, second-, and third-degree relatives of 1,364 nonsyndromic CP probands were estimated to be 2.74% (72/2,628), 0.28% (3/1,068), and 0.00% (0/360), respectively. These estimates are close to published estimates based on questionnaire and interview data. The population prevalence for nonsyndromic CP was, however, found to be considerable higher than usually reported (0.058% [1,456/2,523,023]). Analyses of these and previously published data, using the method presented by Risch, indicated that major-locus or additive multilocus inheritance of CP is unlikely. The familial recurrence pattern was, however, consistent with CP being determined by several interacting loci. Under such a model, a single locus accounting for more than a sixfold increase in the risk to first-degree relatives of CP probands is unlikely, whereas a single locus accounting for a threefold increase provided a good fit to the data. Such a locus could be detected in a realistic sample of affected sib pairs.

Evidence for an association between nonsyndromic cleft lip with or without cleft palate and a gene located on the long arm of chromosome 4

Recent studies suggest that the familial aggregation of nonsyndromic cleft lip with or without cleft palate (CL +/- P) is likely to be attributable to the effects of several susceptibility loci, acting in a multiplicative fashion. Two potential CL +/- P susceptibility loci (CSL), transforming growth factor alpha (TGFA) and retinoic acid receptor (RARA), have been identified through association studies. In addition, recent evidence of linkage between CL +/- P and two markers (D4S175 and D4S192) in the region 4q25-4q31.3 raised the possibility that a CSL, with a larger effect than either TGFA or RARA, may reside within this region of the human genome. The present analyses were undertaken to determine whether D4S175 or D4S192 is significantly associated with CL +/- P in a sample of unrelated patients that have previously provided evidence of associations between CL +/- P and both TGFA and RARA. The results of these analyses provide further, tentative, evidence for the presence of a CSL locus on the long arm of chromosome 4 and help to refine the location of this locus in the region of D4S175 and D4S192.

Sequential analysis of marker data for a rare oligogenic disease

A sequential scheme for identifying genetic markers, in linkage disequilibrium with disease susceptibility loci, was utilized to evaluate potential associations between a rare oligogenic disease and genetic variation at 360 anonymous DNA markers.

Interpreting the evidence for an association between the retinoic acid receptor locus and non-syndromic cleft lip with or without cleft palate

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Are air inlets necessary with Haemaccel?

Haemaccel is often used for the resuscitation of shocked patients. It is common practice to introduce an air inlet into the plastic container to increase the flow rate. We investigated how much difference an air inlet made. We compared the flow rates with no air inlet, a single air inlet, a 2 x 2 cm hole (equivalent to multiple air inlets) and a pressure infusion cuff. Although the use of an air inlet compared with no air inlet reduced the time to infuse 500 ml by 27 s, the difference was only clinically significant over the final 100 ml. A pressure cuff produced the fastest flow, reducing the time by 68 s. Use of an air inlet, however, precludes subsequent use of a pressure cuff. We recommend that the practice of using air inlets for Haemaccel and other similarly packaged products is abandoned.

Evidence for an association between dehydroepiandrosterone sulfate and nonfatal, premature myocardial infarction in males

BACKGROUND

Several studies indicate that endogenous hormones play a role in the etiology of coronary artery disease, either as independent risk factors or indirectly, via an effect on lipids, lipoproteins, or other heart disease risk factors.

METHODS AND RESULTS

The relation between endogenous hormone levels and premature (< 56-year-old patients) myocardial infarction was assessed in a retrospective study involving 49 male survivors of premature myocardial infarction and 49 age-matched, volunteer male controls. Serum samples were obtained for each subject the morning after a > or = 12-hour fast and frozen at -70 degrees C for subsequent hormonal analysis. Among the male patients, the average duration between the most recent myocardial infarction and blood sampling was 3.4 years (range, 0.7 to 19.2 years). Individuals reporting the use of any medications with the potential to alter lipid, lipoprotein, or hormone levels were excluded from these analyses. Dehydroepiandrosterone sulfate levels were significantly lower in the patients than in the control subjects. This association remained statistically significant even after accounting for the effects of total cholesterol, triglycerides, the ratio of total to high-density lipoprotein (HDL) cholesterol, HDL, apolipoprotein A-I, apolipoprotein A-II, apolipoprotein B, and body mass index. There were no significant differences in the levels of estradiol, testosterone, or free testosterone or the ratio of estradiol to testosterone between patients and control subjects.

CONCLUSIONS

Our conclusions are limited by the retrospective nature of this study. However, these data indicate that serum dehydroepiandrosterone sulfate levels are inversely related to premature myocardial infarction in males and that this association is independent of the effects of several known risk factors for premature myocardial infarction.

Commingling analysis of adiposity in an Indian population

The distributions of five adiposity phenotypes were assessed for the presence of commingling in a sample of 756 adults (> or = 30 years old), residing in the Chittoor district of Andhra Pradesh, India. Three measures of generalized fatness (body mass index, the sum of six skinfolds and the sum of three trunk skinfolds) and two indicators of fat patterning (the ratio of trunk to extremity subcutaneous fat and the ratio of the subscapular skinfold to the sum of the subscapular and the supra-iliac skinfolds) were analysed. Each phenotype was adjusted for the effects of (i) age within sex, and (ii) age, energy intake and energy expenditure within sex. The distribution of each phenotype, under both adjustment schemes, was assessed for evidence of commingling. The commingling analyses were performed separately for males (n = 397) and females (n = 359), and evidence for heterogeneity in the distribution of each phenotype, by sex, was evaluated. There is evidence of commingling in the distribution of each phenotype, under both adjustment schemes. Conclusions regarding the distributions of these phenotypes are, however, influenced by the specific adjustments made to the data. In general, the measures of generalized fatness are more sensitive than measures of fat patterning to the specific adjustments applied to the data. Interestingly, and in contrast with the majority of commingling analyses of adiposity, the smallest components of the commingled distributions often have the lowest mean phenotypic value.

The genetics of infantile hypertrophic pyloric stenosis. A reanalysis

OBJECTIVE

To determine whether the existing family data for infantile hypertrophic pyloric stenosis (IHPS) are sufficient for the purposes of establishing the mode of inheritance of this condition.

DESIGN

Reanalysis of the familial aggregation patterns exhibited by IHPS, using data from several published family studies.

CONCLUSIONS

Due to several limitations of the available family data for IHPS, the results of this analysis should be interpreted cautiously. Within the context of these limitations, the familial recurrence pattern among monozygotic cotwins and more remote relatives of IHPS probands was found to be inconsistent with generalized single major locus inheritance. The familial recurrence pattern of IHPS is, however, compatible with multifactorial threshold inheritance or the effects of multiple interacting loci. Under a model of multiple interacting loci, no single locus can account for more than a fivefold increase in the risk to first-degree relatives of IHPS probands. In contrast to several earlier reports, this analysis does not support the existence of a maternal factor that contributes to the risk of IHPS in the offspring of affected females.

The Cincinnati Myocardial Infarction and Hormone Family Study: family resemblance for dehydroepiandrosterone sulfate in control and myocardial infarction families

Dehydroepiandrosterone sulfate (DHEAS) was examined in random (control) and nonrandom (case) families participating in the Cincinnati Myocardial Infarction and Hormone (CIMIH) family study. The case families were ascertained through white men who survived a myocardial infarction (MI) before the age of 56, whereas control families were recruited through advertisements and through an adolescent boy maturation study. Both familial correlations and genetic effects of DHEAS were investigated. First, maximum likelihood estimates of the sex-specific familial correlations (corrected for nonrandom ascertainment) suggested that there was significant heterogeneity between the two sampling types. This heterogeneity was isolated to the male sibling correlation, which was higher in the case than control families. Post hoc analyses suggested that the sibling group heterogeneity may be in part a function of age, since the control sample offspring were on average much younger than those in case families. No sex differences other than those for the siblings were noted in the familial correlations. Second, heritability was investigated in control families using a simple path model (TAU) that allowed for sex differences. The only significant model parameter was the sex-specific familiarity (combined polygenic and familial environmental effects), which was larger in females (74%) than in males (29%). In general, these analyses suggested that (1) DHEAS may play only a limited role in the increased risk for premature MI, and (2) the degree of heritable (familial) variation may be dependent on sex.

Cincinnati myocardial infarction and hormone family study: family resemblance for testosterone in random and MI families

Familial correlations for total testosterone and free testosterone were examined in both random and nonrandom families participating in the Cincinnati Myocardial Infarction and Hormone Family Study (CIMIH). The non-random families were ascertained through Caucasian males who had survived a myocardial infarction (MI) prior to age 56 years, while random families were recruited largely through an adolescent boy maturation study. Eight sex-specific familial correlations were estimated (father-mother, father-son, father-daughter, mother-son, mother-daughter, son-son, daughter-daughter, and son-daughter) for each of the MI and random samples using maximum likelihood methods with appropriate ascertainment correction. These familial correlations were examined for differences between the random and MI samples, as well as for sex-specific familial patterns. The results suggest that total testosterone levels may have a limited role in determining MI risk, as evidenced by the overall heterogeneity between samples, and lower serum levels in MI than random probands. The pattern of correlations for both androgens suggests that a simple genetic model appears unlikely; however, familiarity cannot be ruled out. Although possible covariate effects such as age and sex may have masked some potentially significant results, especially in males, familiarity in females is suggested (correlations ranging from .3-.9). The relative stability of these hormones in females as compared to that in males may have contributed to its identification, and suggests the familial transmissibility may be associated with adrenal production and/or metabolic clearance of testosterone.

Correlates of genetic risk for non-syndromic cleft lip with or without cleft palate

Multivariate analysis was used to determine which characteristics: sex of the proband, sibling sex, severity of the proband's defect or family history, are the best predictors of recurrence risk among siblings of individuals with non-syndromic cleft lip with or without cleft palate (CL +/- P). Sibling recurrence risks are not significantly related to the sex of the proband. Severity of the proband's defect, classified by the extent of the lip defect (unilateral versus bilateral), was found to be a significant predictor of sibling recurrence, whereas involvement of the palate in the proband's defect was not. A positive family history of clefting (i.e. at least one affected first-degree relative in addition to the proband) and the sex of the sibling were also found to be significant predictors of sibling recurrence. The associations between sibling risk and family history, and sibling risk and bilaterality of the proband's defect appear to be mildly confounded. After adjusting for the effects of family history, the risk to siblings of probands with bilateral lip defects is twice the risk to siblings of probands with unilateral defects (O.R. = 2.00; 95% C.I. 1.25-3.19). A positive family history of clefting increases the risk to siblings by greater than 4-fold (O.R. = 4.49; 95% C.I. 2.74-7.35), after adjusting for the extent of the proband's lip defect. These results provide a rational strategy for identifying subsets of the 'at risk' population which have markedly different recurrence risks. This information is important for genetic counseling, since it allows for more precise estimation of sibling recurrence risks in individual cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of adiposity in an Indian population: familial correlations

Familial correlations for five measures of adiposity were assessed using data from 473 nuclear families residing in the Chittoor district of Andhra Pradesh, India. Fat patterning, measured as the ratio of trunk to extremity subcutaneous fat, and the ratio of the subscapular to the sum of the subscapular and suprailiac skinfolds, and three measures of generalized fatness: body mass index, the sum of six skinfolds and the sum of three trunk skinfolds were analyzed. Maximum likelihood estimates of the familial correlations were obtained for each phenotype, after adjusting for the effects of (1) age within sex, and (2) current levels of energy intake and expenditure, and age within sex. Hypotheses regarding sex-specific, and generational differences in these correlations were assessed for each phenotype, under both adjustment schemes. The strength and pattern of the familial correlations for the three measures of generalized fatness were markedly influenced by the specific adjustments applied to the data. In contrast, the familial correlations for the fat patterning phenotypes were quite similar under the two adjustment schemes. Comparison of our results with previously published data indicates that the familial correlations for a subset of these adiposity measures may be heterogeneous across populations.

Mode of inheritance of nonsyndromic cleft lip with or without cleft palate: a reanalysis

Nonsyndromic cleft lip with or without cleft palate (CL +/- P) is traditionally recognized as a multifactorial threshold trait (MFT). Recently, however, evidence for the involvement of a major gene in the etiology of CL +/- P has been reported. To assess the potential for major-gene involvement in the etiology of this trait, familial recurrence patterns from several family studies of CL +/- P were reanalyzed. The recurrence patterns in first-degree relatives of CL +/- P probands were found to be compatible with the expectations for either an MFT or a generalized single-major-locus (gSML) trait. The use of multiple thresholds based on proband sex, defect bilaterality, or palatal involvement did not help to discriminate between these models. However, the pattern of recurrence among MZ twins and more remote relatives of CL +/- P probands is not consistent with gSML inheritance but is compatible with either an MFT model or a model specifying multiple interacting loci. For such a model, no single locus can account for more than a sixfold increase in risk to first-degree relatives. These findings have important implications with regard to the feasibility of detecting linkage to loci conferring susceptibility to CL +/- P.

Hazards of urocanic acid as a cosmetic ingredient

Certain commercially available cosmetic products have been found to contain the ingredient urocanic acid. We have shown that the solar irradiation in vitro of one such lotion resulted in the formation of cis urocanic acid. The irradiated lotion, when applied topically to the skin of hairless mice, systemically suppressed the normal contact hypersensitivity reaction to 2,4-dinitrofluorobenzene by 68%. In addition, mice exposed to a minimally erythemal dose of ultraviolet B (280-320 nm) radiation, normally sub-immunosuppressive, showed a 56% suppression of the contact hypersensitivity reaction if they were irradiated through the topically applied cosmetic lotion.

Reproductive versus chronologic age as a predictor of low birth weight, preterm delivery and intrauterine growth retardation in primiparous women

The effect of reproductive age (chronologic age at conception minus menarcheal age) and chronologic age on the risks of low birth weight, preterm delivery and intrauterine growth retardation were studied in 1198 primiparous women whose pregnancies ended in singleton live births at Yale-New Haven Hospital, 1980-1982. After adjustment for maternal race and other important confounding variables, neither young reproductive age (less than 8 years) nor young chronologic age (less than 20 years) were strongly related to any of the reproductive outcomes. Older chronologic age (greater than 29 years) was also not strongly related to any of these outcomes, but older reproductive age (greater than 15 years) was moderately associated with low birth weight (OR 1.9; 95% CI 0.9, 3.8) after adjusting for maternal race, religion and smoking status. In addition, extremely young reproductive age (less than 2 years) appeared to be associated with an increased risk of preterm delivery (OR 3.1; 95% CI 0.7, 14.6), but our sample was too small to adjust for confounding factors in this group of women. Reproductive age appears to reflect extremes in menarcheal age, whereas chronologic age does not, and this association may account for any relationship between reproductive age and pregnancy risk in primiparous women.

Molecular analysis of an alcohol dehydrogenase (Adh) gene from chromosome 1 of wheat

We have cloned and determined the nucleotide sequence of a gene encoding alcohol dehydrogenase (Adh) from Triticum aestivum cv. Millewa. Southern analysis using cv. Chinese Spring nullisomic-tetrasomic and ditelosomic lines established that the cloned gene mapped to the long arm of chromosome 1A and does not correspond to any previously identified wheat Adh locus. Southern analysis also provided evidence for triplicate copies of this Adh gene on the homoeologous group 1 chromosomes, while Northern blots indicated that the homoeologous group 1 Adh genes, like several other plant Adh genes, are transcribed under anaerobic conditions. Sequence analysis indicates that the cloned gene has a structure similar to both monocot and dicot Adh genes with an open reading frame encoding a polypeptide of 379 amino acids. Sequences important for eucaryotic gene expression such as the TATA box, polyadenylation signal, and intron splice sites were found in the expected positions. The open reading frame is interrupted by 8 introns which are in identical positions with 8 of the 9 introns in maize and pea Adh genes, suggesting that during evolution there are processes occurring that result in the loss of introns. Sequence analysis also revealed that the cloned wheat Adh gene shared extensive homology with the barley Adh3 gene not only in the coding region but also in the noncoding regions. However, this homology is discontinuous as a result of a 1.8-kbp insertion (TLM), which is present in the cloned wheat Adh gene and absent in the barley Adh3 gene. Sequence analysis of this insertion reveals features characteristic of the short terminal inverted repeat class of eucaryotic transposable elements. We have no evidence for the transposition of the TLM element. However, Southern blots reveal multiple copies of sequences related to TLM in the wheat genome and in other closely related species, suggesting that transposition may once have played an important role in the evolution of the Gramineae family.

Collaborative Study of the Infrared Method for DDVP in Pesticide Formulations

A collaborative study, begun in 1963, to evaluate an infrared method for determining the DDVP content of four commercially available formulations, was continvied in 1964. Formulations assayed in 1964 were as follows: 0.5% sugar bait, 4 lb/gallon emulsible concentrate, 0.5% spray solution, and 1.0% cattle spray. Special emphasis was placed on refining the procedure applicable to the low-concentration hydrocarbon solutions. A statistical analysis of the data indicates that results of the test program were satisfactory, and the method is recommended for adoption as official, first action.

Collaborative Study of the Infrared Method for DDVP in Pesticide Formulations

A collaborative study was conducted to evaluate an infrared method for determining the DDVP content of four commercially available formulations: 0.5% sugar bait, 4 1b/gallon emulsible concentrate, 0.5% spray solution, and 1.0% cattle spray. A chloroform extraction procedure and a chloroform dilution procedure gave reproducible results for sugar bait and emulsible concentrate samples, respectively. Two procedures, acetonitrile and solvent compensation, were tried for the lowconcentration hydrocarbon solutions. Neither procedure gave completely satisfactory results and further study is needed.