Background. - The mild errors or morphogenesis (MEMs) are well known and accepted markers of alterations in embryonic development with predictive value in identification of major malformations, specific genetic syndromes, metabolic and psychiatric disease and childhood malignancy.Objective. - The goal of this study was to assess the contribution of auricular MEMs as part of total MEMs in an effort to study the factors influencing the different potential informative value of different types of MEMs and their variability with perinatal factors.Method. - Three thousand one hundred and seven consecutive born neonates were screened for auricular and non-auricular MEMs, inregistered concomitantly with major malformations and postural defects. The study was accomplished by our specially designed computerized program in a relatively large nonhomogeneous ethnic population, in the metropolitan area of Haifa, Israel.Results. - The general prevalence of auricular MEMs was 43.1%; the most frequent pathogenetic type was the postural one. Significantly higher rates of auricular MEMs were associated with male sex, small- and large-for-gestational age, IVF pregnancy, triplet pregnancy, maternal diabetes and parental consanguinity.Conclusion. - We conclude that the presence, number, and association or concomitance of auricular MEMs in the same neonate may have important clinical, diagnostic, pathogenetic, screening, and therapeutic value. (C) 2004 Elsevier SAS. All rights reserved.
Peptide nucleic acids (PNAs) are synthetic homologs of nucleic acids in which the phosphate–sugar polynucleotide backbone is replaced by a flexible pseudo-peptide polymer to which the nucleobases are linked. This structure gives PNAs the capacity to hybridize with high affinity and specificity to complementary sequences of DNA and RNA, and also confers remarkable resistance to DNAses and proteinases. The unique physico-chemical characteristics of PNAs have led to the development of a wide range of biological assays. Several exciting new applications of PNA technology have been published recently in genetics and cytogenetics. Also, PNA-based hybridization technology is developing rapidly within the field of in situ fluorescence hybridization, pointing out the great potential of PNA probes for chromosomal investigations.
A case of de novo acute myeloblastic leukemia (AML) M2, with trisomy 4 and double minute (dmin) chromosomes is reported. Amplification of the MYC gene ascertained by FISH was associated with dmin. A review of the literature of trisomy 4-dmin-associated AML shows that this entity preferentially occurs in elderly women and is not always associated with previously identified exposition to mutagens.
We investigated the genotype and allelic frequency of the -675 bp insertion/deletion polymorphism at the PAI-1 gene promoter, in healthy Mexican subjects. It was compared to the lipid profile and hematological parameters, and to other healthy worldwide populations. A Mexican population sample of 110 individuals was studied. Demographic data and clinical characteristics of the subjects were registered. Fasting lipid profile, serum glucose, fibrinogen, hematological parameters and leukocyte genomic DNA isolation from peripheral blood were performed in all the participants. Screening of the PAI-1 genotype was done by PCR and restriction analysis. Genotype 4G/4G, 4G/5G, 5G/5G frequency in Mexican healthy subjects was: 14.55%, 39.09%, 46.36%, respectively, whereas the allelic frequency for 5G allele was 65.9%. A significant lesser frequency for 4G allele and related genotypes (4G/4G and 4G/5G) was established in healthy subjects from Mexico, respect to all the compared populations. A particular genotype and allelic frequency of this PAI-1 polymorphism was established in Mexico. The clinical parameters were not associated according to each genotype of PAI-1.
The phenotype of maternal uniparental disomy of chromosome 14 (upd(14)mat) is characterized by pre and postnatal growth retardation, early onset of puberty, joint laxity, motor delay, and minor dysmorphic features of the face, hands, and feet. Based on a clinical analysis of 24 cases extracted from the literature the phenotype of upd(14)mat was dissected with respect to each symptom's most likely primary causative: trisomy mosaicism, rare autosomal recessively inherited traits, and the impact of known imprinted genes located on chromosome 14q32. As a result, primary factors are confined placental mosaicism for prenatal growth retardation and one or more imprinted genes, which contribute to the reduced final height by accelerated skeletal maturation. As a secondary effect the latter might also cause early onset of puberty. Other secondary effects might be postnatal adaptation problems associated with neurological deficits such as muscular hypotonia due to premature delivery and reduced birthweight and most dysmorphic features as a consequence of subtle skeletal abnormalities and muscular hypotonia. Considering the rarity of traits such as cleft palate, trisomy mosaicism in the fetus is more likely causative than homozygosity of autosomal recessively inherited mutations. Totally, the variable phenotype of upd(14)mat is mainly the consequence of trisomy mosaicism and genomic imprinting. Rare traits might be due to homozygosity of autosomal recessively inherited mutations.
UNLABELLED:Fetal ultrasound (FU) is used during almost all pregnancies and makes a large contribution to the identification of fetal malformation. It is particularly difficult to announce a malformation, particularly those affecting the brain, because there are often doubts concerning both the diagnosis and the prognosis. AIM:The aim of this study was to analyze how imaging for prenatal screening is organized and how couples are managed and supported. We concentrated on the procedures used to inform couples: content, method of delivery and consequences. METHOD:Study amongst large multidisciplinary centers in Paris and the Paris region, by semi-directed interviews using a questionnaire. RESULTS:We showed that it is difficult to standardize the way in which information is supplied before and after the examination, and that doctors tend to recommend abortion when the prognosis is uncertain. DISCUSSION:These results provide information that will help decision-making concerning a standardized procedure allowing couples to benefit from all the capacities of prenatal screening, particularly when the diagnosis and prognosis are uncertain. There is a need for multidisciplinary teams to support and to accompany the decision concerning whether to have an abortion or to continue the pregnancy.
Rearregements involving long arm of chromosome 12 are rare events. To our knowledge, we present the first case of an interstitial deletion of the long arm of chromosome 12 in a prenatal diagnosis. A review of the literature is included in our report.
We investigated 21 affected individuals in two unrelated monilethrix families of Indian origin and identified point mutation (g.4624G>A) in the HTM motif (exon-7) of the KRTHB6 gene in all the affected members leading to E413K change in this basic keratin. The HTM motif of KRTHB1, however, showed previously unreported two allelic variants, one with three novel variations (SNPs) in cis: g.4421insT (intronic); g.4461T>C (exonic); g.4485A>G (exonic) and second with only intronic variation (SNP) (g.4421insT). Interestingly, the two distinct phenotypes of: localized severe hair defect with beaded appearance confined to the scalp of all the affected members of Family 1 and of generalized unbeaded hair defect of moderate severity in Family 2, segregated in the two families, respectively, correlating with the two separate genotypes for the functionally critical HTM region of KRTHB1 gene in the background of E413K mutation in the KRTHB6 gene. Presence of E413K mutation in the HTM of KRTHB6 gene was not observed in the background of the allelic variant with three SNPs in KRTHB1 gene in homozygous condition in all the affected members of Family 1, affected with a localized but severe form of the disease. However, the same (E413K) mutation existed in the KRTHB6 gene in the background of the allelic variant with three SNPs in the KRTHB1 gene in homozygous condition, consistently in all the affected members of Family 2, where all its affected members showed the segregation of a milder form of the disease. Presence of both E413K mutation in the KRTHB6 and the variations in the KRTHB1 genes were not observed together in randomly selected 150 unaffected controls outside the two affected families. This is also the first report of HTM mutation of KRTHB6 gene in monilethrix cases of Indian origin and the first report of SNPs in the KRTHB1 gene in literature to our knowledge.
Carriers of balanced translocations usually carry alterations in gene sequences, which lead to dysfunction during early and late embryogenesis. Related spatial rearrangement causes either cumulative delay in cell cycles and/or anomalies in transcription and translation. This has also an important impact at the time of genomic activation, the longest cell cycle of preimplantation development. Carrier patients may be affected either with primary infertility or by repeated miscarriages [Hum. Reprod. 12 (1997) 2019.]. Assuming that a fraction of the germ cells is karyotypically normal, these patients would greatly benefit from efficient procedures for generation and use of breakpoint-specific DNA hybridisation probes in preconception and preimplantation genetic diagnosis (PGD) after polar body or blastomere biopsy of the embryos. The objective of this research was to design an approach of patient-specific probes for preimplantation diagnosis of chromosome translocations and which could be used eventually to select chromosomally normal embryos from balanced or unbalanced interphase cells prior to their transfer to the mother’s womb. This approach was used for a couple, where the female partner was a carrier of a balanced translocation 46,XX,t(4;12)(p16.1;q24.31). First, BAC/PAC clones were chosen from specific chromosome bands from the genome sequence that hybridise adjacent to the chromosomal breakpoints or span them. Then, the probes and hybridisation conditions were optimised using unrelated normal amniocytes, lymphoblastoid cells and lymphocytes from the carrier to increase hybridisation signal intensity and decrease background. Finally, the probes were tested on target cells before they were used for mimicking preconception or preimplantation genetic diagnosis. Three slides were analysed blindly from a normal karyotype, an unbalanced and a balanced translocation. A total of 78 cells were analysed of which in the slide A 19/22 (86%) were found to be unbalanced, in slide B 25/31 (81%) were normal and in slide C 21/25 (84%) were balanced. Thus, it was demonstrated that cells with known structural abnormalities could be detected, based on hybridisation of breakpoint spanning bacterial artificial chromosome (BAC) DNA probes in interphase cells.
A systematic cytogenetic study was performed in 49 patients with polycythemia vera (PV) in order to investigate the occurrence of subtelomeric rearrangements of chromosome 20, the most frequently rearranged chromosome in this myeloproliferative disorder. Partial deletion of the long arm of chromosome 20 was observed in two patients and two cryptic translocations, t(1;20)(p36;q13) and t(18;20)(p11;q13) in two others, all previously treated. The localization of the breakpoints of the translocated 20 chromosomes was different in the two translocations, as shown by fluorescence in situ hybridization (FISH) to metaphase chromosomes using BAC clones. Although infrequent (2/49), cryptic translocations of chromosome 20 deserve to be detected as preliminary to identification of molecular defects in PV.
Several reports implicated a relation between the trinucleotide (CAG) repeat length in the androgen receptor (AR) gene and male infertility. But such result was not reproduced in others. To test this hypothesis, we investigated the number of (CAG) repeats in the AR gene among two groups of infertile (n = 129) and fertile Tunisian men (n = 98), using polymerase chain reaction (PCR) targeting the AR CAG repeat tract, followed by electrophoresis on polyacrylamide gel (6%). For statistical analysis we used Student, Kolmogorov-Smirnov (KS) and chi(2)-tests. Significance was reached when P < 0.05. No statistically significant difference in the mean length of the CAG repeat was found between infertile and control groups (P = 0.47). Moreover, using KS test, we have not found a difference in the distribution of allele frequencies between infertile and controls (D(obs) = 0.046 < D(crit) = 0.180). We also did not found a statistically significant relationship between the size of the CAG repeat and impaired sperm production in Tunisian population. Our results may be attributed to the high probability that infertile males may represent a heterogeneous group with respect to the causes of defective spermatogenesis.
We report clinical observations and cytogenetic studies of an inherited partial trisomy 8q and partial monosomy 18p. A full trisomy 8 syndrome (Warkany syndrome) is a clinically recognized syndrome. Partial trisomy 8q has been reported sporadically in the literature with variable phenotypes. Partial monosomy 18p, deletion of the short arm of chromosome 18, is also a well-recognized syndrome. This is the first report to the best of our knowledge of partial trisomy for distal 8q and partial monosomy for distal 18p occurring together in a patient.
We report on a 5-year-old Tunisian boy with particular dysmorphic features and mild mental retardation limited in delayed and poor language acquisition. Cytogenetic analysis using RHG banding and FISH using whole chromosome four painting probe showed a partial duplication in the long arm of chromosome four. Locus specific probes and CGH confirmed the presence of a ‘‘pure’’ partial trisomy 4q due to de novo direct tandem dup(4)(q25q34). Comparative analysis of our case with those published previously, suggests that region 4q31–q33 may be involved in the development of the 4q characteristic dysmorphic features and the distal band 4q35 may be involved in the development of microcephaly and severe mental and growth retardation.
Evidence has emerged that assisted reproduction technology (ART) may be associated with an increased risk of congenital malformations, low birth weight, and genetic imprinting disorders. The aim of the study was to determine, the prevalence of major malformations in newborns conceived by standard in vitro fertilization (IVF) in 1986-1994 and newborns conceived by different types of ART procedures in 1995-2002. Data were collected from the IVF Registry and Israel Birth Defects Monitoring System for all infants (live births, stillbirths and terminations of pregnancy) delivered after 20 weeks' gestation who achieved a fetal weight of at least 500 g. The control groups consisted of all spontaneously conceived babies (live births, stillbirths and terminations of pregnancy) born in our center during the same time periods. During the first period, a total of 31,007 babies were born at our center, of whom 278 were conceived by standard IVF. Twenty-six of the IVF infants had major malformations, for a prevalence rate of 9.35%, which was 2.3-fold higher than that in the general population (4.05%). During the second period, 53,208 infants were born, of whom 1632 were conceived by ART. Major malformations were found in 147 ART infants, for a prevalence rate of 9.0%, which was 1.75-fold higher than in the general population (5.18%). Analysis of the clinical characteristics of the ART infants with major malformations showed that 70.3% were born preterm, 76.5% had low birth weight, 58.6 were twins, and 11.7% were triplets. The use of ART procedures increased by a factor of 3.4 in the second period. Two important outcomes of ART were observed: an increased prevalence of major malformations about double the general population in both periods, and a high frequency of adverse clinical characteristics among ART infants with major malformations. Infertile couples should be adequately counseled regarding the real risk of having a child with malformations or a preterm or low birth weight infant.
Neural tube defects (NTDs) are severe congenital malformations and can be fatal. Intake of 0.4 mg folic in the periconceptional period reduces the risk of NTD by 50-70%. Consanguinity in the Arab population in Israel is a prevalent custom. The aim of this study was to assess the level of awareness regarding folic acid and its effect in the prevention of NTD among Arab Israeli women of childbearing age. We conducted a cross-sectional study. Of the 653 women (18-45 years) who were randomly selected for interview while visiting their family physician or well-baby clinic, 624 women completed the questionnaire. Fifty-three percent (n = 333) of the respondents had heard of folic acid; 14% (n = 89) were familiar with the protective effect of NTD and 3% (n = 18) had taken folic acid in the first months of pregnancy whereas none of them had used it in the preconception period. Highly educated women, women with one or two children, paramedics, and women of high socioeconomic status were more knowledgeable about the protective effects of folic acid (P < 0.001). Age and religion had no significant effect. An urgent need exists to improve the awareness of this population to the protective effect of folic acid. Daily supplementation and fertification of food with folic acid should be considered as the best way to improve the balance of folic acid in women of childbearing age of this special population (high prevalence of consanguinity).
We report tetraploid/diploid mosaicism in a boy and two girls detected by cultured skin fibroblasts. In all these children, interphase-FISH using DXZ1 probe confirmed the original karyotype. Tetraploid mosaicism was also confirmed by α-satellite probes from chromosomes 2, 6, 7, 9, 10, 17, 18 and Y in fibroblasts from the boy. The common features in these children are failure to thrive, slight mental deficiency and some degree of body asymmetry. The advantage of using interphase-FISH is the possibility of analysing a great number of cells in short time, thus giving a more precise percentage with regard to abnormal cells.
