Maternal LINE-1 DNA Methylation and Congenital Heart Defects in Down Syndrome

Background: Down syndrome (DS) is one of the most common chromosomal abnormalities associated with congenital heart defects (CHD), with approximately 40 to 60% of cases showing cardiac defects. This study assessed (i) the association between maternal LINE-1 methylation and the occurrence of CHDs in children with DS and (ii) the impact of endogenous maternal factors (MTHFR C677T polymorphism and maternal age) and exogenous maternal factors (cigarette smoking, alcohol intake, medication use, body mass index and dietary habits such as folate intake) on maternal LINE-1 methylation and on the occurrence of CHD in children with DS.

Patients and Methods: The study included 90 mothers of children with DS of maternal origin (49% DS-CHD⁺ mothers/51% DS-CHD⁻ mothers). LINE-1 DNA methylation was analyzed in peripheral blood lymphocytes by quantification of LINE-1 methylation using the MethyLight method. MTHFR C677T polymorphism genotyping was performed using PCR-RFLP.

Results: LINE-1 methylation was not significantly different between DS-CHD⁺ and DS-CHD⁻ mothers (P = 0.997). Combination of MTHFR C677T genotype/diet and BMI were significant independent predictors of LINE-1 DNA methylation in DS-CHD⁺ mothers (β −0.40, P = 0.01 and β −0.32, P = 0.03, respectively). In the analyzed multivariate model (model P = 0.028), these two factors explained around 72% of the variance in LINE-1 DNA methylation in mothers of children with DS and CHD. The group with the highest BMI (≥30 kg/m2) had significantly lower LINE-1 methylation than the group with normal BMI (Bonferroni post hoc P = 0.03) and the overweight group (Bonferroni post hoc P = 0.04). The lowest LINE-1 DNA methylation values were found in DS-CHD⁺ mothers with the CT+TT genotype and a low-folate diet; the values were significantly lower than the values in mothers with the CC genotype and a folate-rich diet (Bonferroni post hoc P = 0.04).

Conclusion: Association between maternal LINE-1 methylation and CHD in children with DS was not found. Study showed that the MTHFR genotype/diet combination and BMI were significantly associated with LINE-1 methylation in mothers of children with DS-CHD⁺. These results highlight the need for a multifactorial approach to assess the roles of endogenous and exogenous maternal factors in maternal LINE-1 DNA methylation and the consequent pathologies in children. More extensive studies in a larger sample may help elucidate these relationships.

No association of CCR5D32 gene mutation with multiple sclerosis in Croatian and Slovenian patients

Several studies investigating the role of the CCR5D32 mutation in multiple sclerosis (MS) have reported varied, often contradictory results. Therefore in the present study we have analysed whether the CCR5D32 mutation is associated with the risk of/or disease process in Croatian and Slovene MS patients. Three hundred and twenty-five MS patients and 356 healthy controls were genotyped by the polymerase chain reaction method. Our results showed no significant differences in the distribution of CCR5D32 mutations between MS and control subjects, indicating that this mutation does not influence susceptibility to MS. Furthermore, we did not observe that CCR5D32 carrier-status could modulate age of disease onset or progression of the disease. It is therefore our conclusion that the present study indicates that the CCR5D32 mutation is neither protective of, nor a risk factor, for MS development.

Altered LINE-1 Methylation in Mothers of Children with Down Syndrome

Down syndrome (DS, also known as trisomy 21) most often results from chromosomal nondisjunction during oogenesis. Numerous studies sustain a causal link between global DNA hypomethylation and genetic instability. It has been suggested that DNA hypomethylation might affect the structure and dynamics of chromatin regions that are critical for chromosome stability and segregation, thus favouring chromosomal nondisjunction during meiosis. Maternal global DNA hypomethylation has not yet been analyzed as a potential risk factor for chromosome 21 nondisjunction. This study aimed to asses the risk for DS in association with maternal global DNA methylation and the impact of endogenous and exogenous factors that reportedly influence DNA methylation status. Global DNA methylation was analyzed in peripheral blood lymphocytes by quantifying LINE-1 methylation using the MethyLight method. Levels of global DNA methylation were significantly lower among mothers of children with maternally derived trisomy 21 than among control mothers (P = 0.000). The combination of MTHFR C677T genotype and diet significantly influenced global DNA methylation (R2 = 4.5%, P = 0.046). The lowest values of global DNA methylation were observed in mothers with MTHFR 677 CT+TT genotype and low dietary folate. Although our findings revealed an association between maternal global DNA hypomethylation and trisomy 21 of maternal origin, further progress and final conclusions regarding the role of global DNA methylation and the occurrence of trisomy 21 are facing major challenges.

Low frequency of HFE gene mutations in Croatian patients suspected of having hereditary hemochromatosis

Background

Hereditary hemochromatosis (HH) is a common autosomal recessive disorder in populations of European descent. It is characterized by a variable prevalence of mutations in the hemochromatosis gene (HFE) in different countries and a complex relationship between the HFE genotype and the HH phenotype. Genetic analysis has not been conducted in Croatian patients with iron overload. The aim of this study was to determine whether HFE mutations, C282Y, H63D, and S65C were correlated with clinical and biochemical parameters in Croatian patients with suspected HH.

Material/Methods

Clinical examination, biochemical analysis, and genotyping were performed in 175 patients suspected of having HH. The control group consisted of 350 healthy blood donors.

Results

Among the patients, 20% had genotypes related to HH – 7.4% were homozygous for C282Y, 6.3% were compound heterozygous for C282Y and H63D, 5.7% were homozygous for H63D, and 0.6% was compound heterozygous for C282Y and S65C. The allelic frequencies were 14.6% for C282Y mutation, 23.7% for H63D mutation, and 1.4% for S65C mutation. A comparison of the clinical and laboratory profiles of patients revealed that C282Y homozygotes had higher frequencies of all clinical symptoms and higher levels of biochemical parameters than others. The C282Y/H63D compound heterozygotes and H63D homozygotes were found to be clinically important, despite the fact that they were associated with less severe disease.

Conclusions

Our results show that HFE mutations are responsible for only about 20% of Croatian patients with suspected HH. Screening with biochemical methods and HFE genotyping may be not sufficient for diagnoses in the Croatian population.

Down syndrome: parental origin, recombination, and maternal age

The aims of the present study were to assess (1) the parental origin of trisomy 21 and the stage in which nondisjunction occurs and (2) the relationship between altered genetic recombination and maternal age as risk factors for trisomy 21. The study included 102 cases with Down syndrome from the Croatian population. Genotyping analyses were performed by polymerase chain reaction using 11 short tandem repeat markers along chromosome 21q. The vast majority of trisomy 21 was of maternal origin (93%), followed by paternal (5%) and mitotic origin (2%). The frequencies of maternal meiotic I (MI) and meiotic II errors were 86% and 14%, respectively. The highest proportion of cases with zero recombination was observed among those with maternal MI derived trisomy 21. A higher proportion of telomeric exchanges were presented in cases with maternal MI errors and cases with young mothers, although these findings were not statistically significant. The present study is the first report examining parental origin and altered genetic recombination as a risk factor for trisomy 21 in a Croatian population. The results support that trisomy 21 has a universal genetic etiology across different human populations.

MTHFR C677T and A1298C polymorphisms as a risk factor for congenital heart defects in Down syndrome

BACKGROUND

Congenital heart defects (CHD) are present in most, but not all, cases of Down syndrome (DS). The presence of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms has been reported as a risk factor for CHD in DS. The aims of the present study were to assess (i) the frequency of MTHFR C677T and A1298C polymorphisms in DS individuals in the Croatian population; (ii) the relationship between the two maternal MTHFR polymorphisms and CHD-affected DS children; and (iii) the transmission frequencies of the variant alleles of the two MTHFR polymorphisms in CHD-affected DS.

METHODS

The study population included 112 DS subjects and 221 controls. CHD were present in 48% of the DS subjects (54/112). The mothers of 107 DS individuals were available for the study; none was a periconceptional folic acid user. Allele transmission was analyzed in 34 complete parent-offspring triads.

RESULTS

The frequencies of the allele, individual, and combined genotypes of MTHFR C677T and A1298C in DS subjects were not statistically different compared to the normal healthy Croatian controls. The maternal MTHFR polymorphisms were not found to be a risk factor for DS-related CHD. The allele transmission of the two MTHFR polymorphisms showed no deviations from random segregation.

CONCLUSIONS

Because the fetus is lost in a great proportion of trisomy 21 pregnancies, both maternal and fetal, not only live-born MTHFR C677T and A1298C, as well as maternal nutrition and lifestyle during pregnancy, should be analyzed to asses the impact on CHD in DS.

Functional inference of methylenetetrahydrofolate reductase gene polymorphisms on enzyme stability as a potential risk factor for Down syndrome in Croatia

Understanding the biochemical structure and function of the methylenetetrahydrofolate reductase gene (MTHFR) provides new evidence in elucidating the risk of having a child with Down syndrome (DS) in association with two common MTHFR polymorphisms, C677T and A1298C. The aim of this study was to evaluate the risk for DS according to the presence of MTHFR C677T and A1298C polymorphisms as well as the stability of the enzyme configuration. This study included mothers from Croatia with a liveborn DS child (n = 102) or DS pregnancy (n = 9) and mothers with a healthy child (n = 141). MTHFR C677T and A1298C polymorphisms were assessed by PCR-RFLP. Allele/genotype frequencies differences were determined using χ² test. Odds ratio and the 95% confidence intervals were calculated to evaluate the effects of different alleles/genotypes. No statistically significant differences were found between the frequencies of allele/genotype or genotype combinations of the MTHFR C677T and A1298C polymorphisms in the case and the control groups. Additionally, the observed frequencies of the stable (677CC/1298AA, 677CC/1298AC, 677CC/1298CC) and unstable (677CT/1298AA, 677CT/1298AC, 677TT/1298AA) enzyme configurations were not significantly different. We found no evidence to support the possibility that MTHFR polymorphisms and the stability of the enzyme configurations were associated with risk of having a child with DS in Croatian population.

Stress and anxiety in relation to amniocentesis: do women who perceive their partners to be more involved in pregnancy feel less stressed and anxious?

AIM

To assess whether imminent amniocentesis is associated with the perception of increased stress and state anxiety in women and their partners and whether greater partner's involvement during pregnancy alleviates women's stress and anxiety.

METHODS

Two hundred twenty women awaiting amniocentesis and 90 male partners participated in the study. The State-Trait Anxiety Inventory, Perceived Stress Scale, and Partner's Involvement in Pregnancy Scale were administered. Statistical analysis was performed using t test, one way ANOVA, and Pearson correlation test.

RESULTS

Imminent amniocentesis caused increased stress (17.6 +/- 6.8; t = 7.32, P < 0.001) and anxiety (42.0 +/- 11.9; t = 8.51, P < 0.001) in pregnant women, but not their partners (stress: 14.3 +/- 6.1; t = 0.17, P = 0.862; anxiety: 36.4 +/- 10.40; t = 0.66, P = 0.510). Stress was even more pronounced in women who experienced another stressor, like unplanned pregnancy, prenatal-related nausea and vomiting, or chromosomal aberration in a previous pregnancy. Significant negative correlation was found for women's stress and their perception of their partner's involvement during pregnancy (r = -0.23; P = 0.001); the same was not found for women's anxiety.

CONCLUSION

Greater partner's involvement during pregnancy could diminish women's stress, but elevated state anxiety just before amniocentesis could not be alleviated in the same way. Thus, health care professionals must pay greater attention to the psychological status of women undergoing amniocentesis to help them better cope with the situation.

Severe psychomotor retardation in a boy with a small supernumerary marker chromosome 19p

We describe the clinical case of a nine-year-old boy with psychomotor retardation and a small supernumerary marker chromosome (sSMC) present in mosaic form. Fluorescence in situ hybridization (FISH) using centromere cross-hybridizing probes D1/5/19Z (pZ5.1), the whole chromosome paint probe 19, pool YACs19p (839B1, 872G3, 728C8), and pool YACs19q (767C4, 761C1, 786G6) demonstrated that the sSMC was derived from chromosome 19p. Based on GTG-banding and FISH analyses, the patient's karyotype was interpreted as: 47,XY,+mar.ish der(19) (:p13.3-->p11:)(839B1+, 872G3+,728C8+, D1/5/19Z+) de novo[52]/46,XY[48]. To our knowledge, only two other similar cases have been reported. This case helps to better delineate karyotype-phenotype correlations between sSMC 19p and associated clinical phenomena.

Prenatal diagnosis of complete trisomy 19q

This communication presents the first case of complete trisomy 19q, prenatally detected by ultrasound investigation. Real-time high-resolution ultrasound examination was performed at 19 weeks of gestation. After termination of the pregnancy, autopsy investigation was done. GTG-banding, fluorescence in situ hybridization m-(FISH) analysis, and FISH analysis with a 19q subtelomeric specific probe were used for identification of the fetal karyotype. Sonographic examination revealed an enlarged cisterna magna, cerebellar hypoplasia and aplasia of the inferior part of the vermis, combined and bilateral kidney malformations, significant nuchal fold, absence of fetal nasal bones, and intracardial calcifications. Autopsy confirmed ultrasound findings, but also revealed situs viscerum inversus of the lungs. Fetal karyotype was defined as: 46,XY,der(21)t(19;21)(q11;p13)mat. Our ultrasound and autopsy findings will certainly contribute to better knowledge of phenotype characterization of this rare chromosomal disorder.

HLA class II polymorphism in autochthonous population of Gorski kotar, Croatia

The aim of this study was to examine frequencies and haplotypic associations of HLA class II alleles in autochthonous population of Gorski kotar (Croatia). HLA-DRB1, -DQA1 and -DQB1 alleles were determined by DNA based PCR typing in 63 unrelated inhabitants from Gorski kotar whose parents and ancestors were born and lived in tested area for at least over four generations. A total of 13 HLA-DRB1, 12 DQA1 and 14 DQB1 alleles were identified. The most frequent HLA class II genes in Gorski kotar population are: HLA-DRB1*13 (af = 0.150), -DRB1*03 (af = 0.142), -DRB1*07 (af = 0.119), and -DRB1*11 (af = 0.119), HLA-DQA1*0501 (af = 0.278), -DQA1*0102 (af = 0.183), -DQA1*0201 (af = 0.127) and HLA-DQB1*0301 (af = 0.157), -DQB1*0201 (af = 0.139), -DQB1*0501 (af = 0.111). We have identified 24 HLA class II three-locus haplotypes. The most common haplotypes in Gorski kotar population are DRB1*03-DQA* 0501-DQB1*0201 (0.120), DRB1*11-DQA1*0501-DQB1*0301 (0.111) and DRB1*07-DQA1*0201-DQB1*0202 (0.094). The allelic frequencies and populations distance dendrogram revealed the closest relationships of Gorski kotar population with Slovenians, Germans, Hungarians and general Croatian population, which is the result of turbulent migrations within this microregion during history.

The prevalence of live birth Down syndrome in the region of Primorsko-goranska County in Croatia, 1996-2005: the impact of screening and amniocentesis

OBJECTIVES

To investigate the prevalence of live birth Down syndrome (DS) in the region of Primorsko-goranska County (PGC) in Croatia from 1996 to 2005 and to evaluate the impact of second-trimester maternal serum screening (MSS) and amniocentesis on live birth DS prevalence.

METHODS

Study was based on databases from the Department of Gynecology and Obstetrics, University Hospital Centre Rijeka, the Department of Biology and Medical Genetics, School of Medicine, University of Rijeka, and the Croatian National Institute of Public Health. The regional policy of prenatal diagnosis for DS includes amniocentesis for pregnant women aged 35 or over and MSS for younger women. We estimated live birth and total prevalence of DS and measured the proportion of pregnant women using MSS and amniocentesis. Trends of live birth and total prevalence of DS were tested by linear regression analysis.

RESULTS

The live birth prevalence of DS was 1.4/1000 in the period 1996-2005. A decreasing, but nonsignificant, trend of prevalence was observed over time (P = 0.577). Women aged 35 or over represented 11.6% of all pregnant women included in the study. The proportion of women who had MSS was 33.9%. The proportion who underwent amniocentesis was 6.1%.

CONCLUSIONS

No marked decrease in prevalence of live birth DS was observed in the region of PGC during the last 10 years. The usage of MSS and amniocentesis was too low to have any significant impact on live birth DS prevalence. Women's, as well as physician's, knowledge and attitudes towards prenatal diagnosis of DS should be evaluated.

Tumor necrosis factor-alpha-308 gene polymorphism in Croatian and Slovenian multiple sclerosis patients

Previous findings regarding the role of TNF-alpha-308 gene polymorphism in multiple sclerosis (MS) are contradictory. The aim of this study was to investigate the possible influence of TNF-alpha-308 polymorphism on MS susceptibility and the MS disease process in a Croatian and Slovenian population. Genotyping was performed in 338 patients and 460 healthy controls. The TNF2 allele was present in 123 (26.8%) healthy controls vs. 67 (19.9%) MS patients (p = 0.023, odds ratio = 0.68, 95% confidence interval = 0.48-0.95), suggesting that carriage of the TNF2 allele might decrease MS risk. The difference in TNF2 allele carrier frequency between patients and controls was identified in the relapsing-remitting MS group. There was no association between TNF2 allele carrier status and age at disease onset or disease progression. Our results suggest that, in the study populations, the TNF-alpha-308 polymorphism may play a role in MS susceptibility.

Region with persistent high frequency of multiple sclerosis in Croatia and Slovenia

OBJECTIVE

The aim of this study was to evaluate the prevalence of multiple sclerosis (MS), and to determine the clinical characteristics and the occurrence of familial MS in the Gorski kotar-Kocevje region, which was previously considered to be a region of high prevalence of MS.

METHODS

All clinically and laboratory supported definite cases of MS according to Poser's criteria, living residents of the chosen area on June 1, 1999 were included in the study. The patients were ascertained through national case registers for MS at the University Medical Centers (Rijeka and Ljubljana), registries of the national associations of MS patients, as well as from the medical records of regional outpatient clinics.

RESULTS

The crude annual prevalence per 100,000 population was 151.9 (95% CI 123.2-187.4). 28.7% of patients had a history of MS among first-, second-, or third-degree relatives. The frequency of primary progressive course of disease was 23.5%. The sex ratio (F/M) was 1.41.

CONCLUSION

A stable high prevalence of MS as well as a high number of familial MS cases was identified in the neighbouring regions of Slovenia and Croatia.

Mutations in the hemochromatosis gene (HFE) and multiple sclerosis

In the present study we have investigated whether HFE gene polymorphism may play a role in the disease process of Croatian and Slovenian MS patients and their potential genetic susceptibility to MS. We genotyped 314 MS patients and 400 healthy controls for the C282Y and H63D mutations by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) analysis. Our results showed no significant differences in the distribution of the two mutations between MS patients and controls, suggesting that HFE polymorphisms do not contribute to the susceptibility to MS. Also, there was no significant correlation between HFE polymorphism and the disease progression index. However, we observed that MS patients carrying the mutant C282Y allele exhibited earlier onset of disease symptom relative to other genotypes, but it warrants further study in a larger series of MS patients.

Frequency of CCR5 gene 32-basepair deletion in Croatian normal population

A 32-basepair deletion polymorphism in the CCR5 chemokine receptor gene (CCR5 TROKUT 32) could increase the resistance to HIV-1 infection or delayed progression to AIDS. This mutant allele is common among Caucasians of Western European descent, but has not been observed in people of African or Asian ancestry. Genetic studies provided in European countries have shown a highest prevalence in Nordic countries and the lowest in the Southern European and Mediterranean populations. We genotyped 303 randomly selected healthy Croatians for the prevalence of CCR5 TROKUT 32 mutation. CCR5 TROKUT 32 allele frequency in Croatia of 7.1% fits in the observed European north/south gradient. This first report of CCR5 TROKUT 32 mutation in Croatian population provides additional information on its frequency and geographical distribution in Slavic populations in South-Eastern Europe. Moreover, our data may have important implications for the prediction and prevention of HIV/AIDS in a tourist country such as Croatia.

Elevated second-trimester free beta-hCG as an isolated finding and pregnancy outcomes

OBJECTIVE

To investigate the relationship between unexplained elevated second-trimester free beta-human chorionic gonadotropin (beta-hCG) levels and pregnancy complications as well as adverse pregnancy outcomes.

METHODS

The study cohort comprised 2,110 non-smoking women with chromosomal and structurally normal fetuses at low-risk for both Down's syndrome (risk <1:250) and neural tube defects (maternal serum alpha-fetoprotein <2.0 MoM). A free beta-hCG value of > or =2.0 MoM was used to define the populations with elevated levels of free beta-hCG. Descriptive statistics, chi2 test, Fisher's exact test, and logistic regression analysis were used for statistical analysis, and p < 0.05 was considered statistically significant.

RESULTS

The mean maternal age of the study group was significantly lower than in controls (27.9 +/- 4.3 and 30.6 +/- 5.1 years, respectively, p < 0.05), while the proportion of primigravidas was significantly higher compared to that of controls (p < 0.05). After adjustment of the 2 groups according to maternal age and parity, we observed an increased incidence of preeclampsia among women with elevated free beta-hCG levels in relation to controls (p < 0.05). However, a logistic regression analysis demonstrated that the free beta-hCG level was not a predictor of the occurrence of preeclampsia. No significant relationship was found with the incidence of gestational diabetes, oligohydramnios, polyhydramnios, pregnancy-related hypertension, intrauterine growth retardation, preterm delivery, spontaneous abortion and stillbirths (p > 0.05).

Secular change in body height and cephalic index of Croatian medical students (University of Rijeka)

An investigation of body height and cephalic measurements was performed among five groups of first-year medical students of the University of Rijeka School of Medicine (Rijeka, Croatia). Body height and different cephalic measurements showed normal distribution, both in male and female students. Differences between measured variables were statistically analyzed by ANOVA. No significant difference with regard to year of birth was found in either males or females. The cephalic index showed no statistically significant difference between sexes or with regard to body height, while head breadth and length correlated significantly with birth year and body height, both in males and females. Head breadth decreased within the study period, while head length increased. Results were compared with those of similar studies from the mid-20th century. Student's t-test showed a significant change of cephalic indices and other head measurements, but not of body height, in males. The frequency difference between various head shapes was tested using the chi-square test. A significant increase of dolichocephalic and mesocephalic and a significant decrease of brachycephalic head shape were found in both sexes. These results suggest a continuity of the debrachycephalization process observed in our population at the past midcentury.

The influence of smoking and parity on serum markers for Down's syndrome screening

OBJECTIVE

To evaluate the impact of smoking and number of previous births on maternal serum levels of alpha-fetoprotein and free beta-subunit of human chorionic gonadotropin (free beta-hCG).

METHODS

The study included 3,252 completed unaffected singleton pregnancies that proceeded beyond 37 weeks' gestation and resulted with a birth of healthy child. Smoking status of mothers and data concerning gravidity and parity were collected at the sampling date. Serum markers were measured between 13 and 22 gestational weeks, corrected for maternal weight, and converted to multiples of median (MoM) for unaffected pregnancy of the corresponding gestational age. Median MoM values for both markers were examined in relation to both: smoking habits and number of previous births.

RESULTS

Smokers had significantly decreased free beta-hCG MoM values compared to nonsmokers (p < 0.001). The median levels showed a negative relationship with the number of previous births. The significance of a decreasing trend was proved, both in smokers (p < 0.001) and nonsmokers (p < 0.001). The median maternal serum alpha-fetoprotein MoM values did not show any significant dependence, neither with regard to smoking (p = 0.65) nor with regard to parity (p = 0.07).

CONCLUSIONS

The recommendable adjustment of serum markers to smoking habits, especially concerning the free beta-hCG levels, would be worthwhile. The evidence of the coexisting influence of parity on serum levels of free beta-hCG, both in smokers and nonsmokers, should perhaps be a stimulus for reconsideration of which corrections the screening performance is dependent on.

The effect of a compulsory curriculum on ethical attitudes of medical students

The purpose of the present study was to assess the influence of a compulsory curriculum on first-year medical students. The ethical attitude study was performed at the School of Medicine, University of Rijeka, Croatia. The samples consisted of 171 medical students (68 males and 103 females) interviewed at the beginning of the first year of studies. Some of them, namely 143 (56 males and 87 females) were interviewed again at the end of the same academic year. Data were analysed by applying factor analysis under principal component model and varimax criterion as the rotation model. The results clearly show that the current compulsory curriculum without formal ethical education has a limited influence on first-year medical students. That points to the obvious necessity to implement the medical ethics in the course of medical education.

Partial trisomy 13q22-->qter and monosomy 18q21-->qter as a result of familial translocation

We report on a patient with a partial trisomy of chromosome 13q22-->qter and partial monosomy of chromosome 18q21-->qter showing distinct malformations. The phenotype of this unbalanced karyotype has not been previously described. The proband had a craniofacial dysmorphism, neck pterygium, closed fists with overlapping fingers, cutaneous appendix of the left fist, equinovarus and postaxial hexadactyly of the feet, atrial septum defect, unilateral cryptorchidism and hypertrophic pyloric stenosis. Using fluorescence in situ hybridization (FISH) the father's karyotype 46,XY.ish t(13;18)(13pter-->13q22::18q21-->18qter; 18pter-->18q21::13q22-->13qter) and the child's 46,XY.ish der(18)(18pter-->18q21::13q22-->13qter)pat were established. The mother's karyotype was normal. A risk of unbalanced offspring in carriers of a balanced reciprocal translocation depends on the length and genetic constitution of the exchanged segments. Risk figures should come only from empirical data. A phenotypically normal child with a balanced or normal karyotype could be born in the case of alternate segregation. Amniocentesis should therefore be recommended in any further pregnancy.

Screening for Down's syndrome and neural tube defect in Croatia. A regional prospective study

OBJECTIVE

The purpose of this study was to investigate the efficiency of second-trimester maternal serum screening for Down's syndrome and open neural tube defects using alpha-fetoprotein and free beta-human chorionic gonadotropin as serum markers.

METHODS

3, 188 women underwent testing between 14th and 22nd week of pregnancy. Of all tested patients, 25.4% were >/=35 years old. A cut-off risk of >/=1:250 for Down's syndrome and MS-AFP >/=2.0 MoM for open neural tube defect were considered screen-positive.

RESULTS

The detection rate for Down's syndrome was 77.8% (7/9) with 8.2% screen-positive rate (7.9% false-positive rate). When evaluated separately, in patients younger than 35 and in those >/=35 years old, the screen-positive rates were 3.1 and 23.3%, respectively. A total of 52 (1.6%) were found screen-positive for open neural tube defect; 2 cases of encephalocela and 1 case of gastroschisis were confirmed prenatally.

CONCLUSION

The respectable number of cases with trisomy 21 identified in this study confirms that routine mid-trimester screening for Down's syndrome including MS-AFP, free beta-hCG and maternal age is useful in identifying pregnancies at increased risk.

Chromosomal anomalies in abnormal human pregnancies

OBJECTIVE

The aim of this study was to describe the cytogenetic observations on abnormal human pregnancies (anembryonic pregnancy, early fetal loss, and hydatidiform moles), and to detect the most frequent or typical chromosomal aberration for anembryonic pregnancy and early fetal loss.

STUDY DESIGN

Abnormal pregnancies were divided into three clinical and morphological groups: (a) anembryonic pregnancy; (b) early fetal loss, and (c) hydatidiform mole. Of the 119 karyotyped tissue samples, 42 (35%) were from anembryonic pregnancies, 64 (54%) from early fetal losses, and 13 (11%) were from hydatidiform moles (6 complete and 7 partial moles). Long-term cultures of chorionic villi and GTG-banding techniques were used for chromosome analysis.

RESULTS AND CONCLUSION

The overall frequency of chromosome anomalies among the 119 karyotyped spontaneous abortions was found to be 37.8%. Trisomy (double trisomy included) accounted for 35.6% of all aberrations, followed by polyploidy (33.3%), mosaicism (11.1%), structural abnormalities (4.4%), and monosomy X (2.2%). Although the difference was not statistically significant, single trisomy was the predominant chromosome abnormality found in anembryonic pregnancies (64.3 %) while in cases of early fetal loss, trisomy (double trisomy included) (38.9%) and triploidy (27.8%) were quite frequently present. The frequency of triploidy among all chromosomal abnormalities was 28.9%, and 53.8% of them were found in partial hydatidiform mole. The rest of them were almost exclusively found in early fetal losses. Complete hydatidiform moles (androgenetic in origin) were present in 13.3% of all aberrations, of which 83.3% had a 46,XX, and the rest of them had a 46,XY karyotype.