Genomic chondrocyte culture profiling by array-CGH, interphase-FISH and RT-PCR.

OBJECTIVE: In vitro expansion is an important step to acquire sufficient cells in human tissue engineering technologies. The high number of chondrocytes needed for human articular cartilage implants requires in vitro expansion of the primary cells, bearing a theoretical risk of in vitro induced changes in the genomes. To gain more insights into this situation, model cultures were prepared and analyzed. DESIGN: 25 chondrocyte cell DNA samples from nine donors were analyzed by array comparative genomic hybridization (aCGH) on whole genome level and 28 chondrocyte cell samples from 16 individuals were analyzed by fluorescence in situ hybridization (FISH) on single cell level. The expanded cells were further characterized upon the chondrocytic mRNA phenotype by reverse-transciptase polymerase chain reaction (RT-PCR). RESULTS: The molecular karyotyping results revealed autosomal stability, but all male samples analyzed by aCGH displayed a variable loss of the Y-chromosome. These data were confirmed by FISH-experiments and suggest an age dependant effect toward the loss of the Y-chromosome in cultured chondrocytes. RT-PCR data for the mRNAs from collagen types I, II, and aggrecan and the pro-inflammatory cytokine interleukin-1ß (IL-1ß) did not reveal any correlation of transcriptional activity in cultures with Y-chromosome losses, nor were there statistically significant differences between cells from female and male donors. CONCLUSIONS: While cells of male origin may suffer from an age-related loss of the Y-chromosome, there was no indication of a functional impairment. The data suggest some caution toward applying proliferative steps when considering chondrocytes from elderly male patients for tissue engineering approaches.

The impact of first trimester screening and early fetal anomaly scan on invasive testing rates in women with advanced maternal age.

PURPOSE: To evaluate the acceptance of noninvasive screening for trisomy 13, 18, 21 and the impact on invasive testing rates in women at an age≥35 years. MATERIALS AND METHODS: In a retrospective analysis from 2003-2006 including 13 268 women≥35 years old with singleton pregnancies and 3133 invasive procedures, we evaluated the prenatal detection rate of aneuploidies in two cohorts. Group 1: advanced maternal age as sole indication, group 2: additional abnormalities and/or suspicious maternal serum parameters. In an additional analysis from 1998-2006 including 31,076 patients≥35 years, we investigated the shift in time of sonography at 11+0-13+6, 14+0-17+6 and 18+0-22+6 gestational weeks (gw). RESULTS: Among 13,268 women, 3133 invasive tests were performed with a significant decrease over time (-17%). 9% of women chose invasive testing after a normal ultrasound (group 1, n=1,267) and 14% in the case of additional markers (group 2, n=1,866). 102 cases of aneuploidy were disclosed. The proportion of detected aneuploidies was 0.86% in group 1 and 4.9% in group 2. No change in the overall detection rate (90-93%) was observed. The number of patients≥40 years increased significantly (+2.8%). There was an increase in examinations at 11+0-13+6 gw (+8%), a decrease at 14+0-17+6 gw (-10.3%) and no significant change at 18+0-22+6 gw over time. CONCLUSION: Increasing numbers of women≥35 years of age rely on the individually adjusted risk figure to make a decision about invasive testing. The application of these selective procedures can reduce the rates of invasive testing with fewer losses of normal fetuses and led to an earlier diagnosis of aneuploidies.

Dystocia and fetotomy associated with cerebral aplasia in a greater one-horned rhinoceros (Rhinoceros unicornis).

The captive greater one-horned rhinoceros population consists of 176 animals. Since 1971, a total of 226 calves were born into this captive population. However, 24% of the offspring born were either stillborn or did not survive the first 3 months. The causes for this high rate of stillbirth and neonate mortality have not yet been documented. Here, we report on the veterinary management of a dystocia and foetotomy resulting from a malpositioned greater one-horned rhinoceros foetus. The dead foetus presented with a forelimb flexed at the shoulder joint, with all other joints extended. The foetus was dissected into five parts and extracted during two anaesthesias on two consecutive days. The dam recovered fully and came into oestrous 31 days after surgery. Post-mortem and CT examination of the malformed foetal head revealed cranioschisis with cerebral aplasia and cerebellar hypoplasia. The cerebral aplasia presented here and in other recent cases suggests that neural tube defects and cranial malformations may be associated with more captive rhinoceros stillbirths than previously considered. Epidemiologic studies of these phenomena and possible nutritional deficiencies or hereditary defects are warranted.

A mixture model of nuchal translucency thickness in screening for chromosomal defects: validation of a single operator dataset.

OBJECTIVE: (1) To validate the mixture model in a single operator dataset and (2) to compare the detection rates for fetal chromosomal defects obtained from the mixture model with those obtained from either the delta nuchal translucency (NT) or log multiple of the median (MoM) approach. METHODS: Database query, viable singletons [crown-rump length (CRL) 45-84 mm corresponding to 11-13(+6) weeks], December 1997 to November 2006, examined by Adam Gasiorek-Wiens, the statistical mixture model was applied. RESULTS: Seventy-four of 4171 were lost to follow-up (1.8%), 4097 singleton pregnancies included trisomy 21 (n = 34, 0.8%), trisomy 18 (n = 20, 0.5%), trisomy 13 (n = 8, 0.2%), Turner syndrome (n = 9, 0.2%) and other chromosomal abnormalities (n = 14, 0.3%). The main findings are that (1) the log-transformed NT measurements follow a mixture of two Gaussian distributions and (2) the criteria to apply either the delta-NT or log MoM models are not met. In the normal group, the majority of NT measurements were dependent on the CRL, a small group showed a median independent of the CRL. In the abnormal group it was the opposite. For a 5% false-positive rate (FPR), the trisomy 21 detection rate was 83%. CONCLUSIONS: The use of the mixture model in a single operator dataset produces results compatible with the original study. The mixture model has thus been validated.

First-trimester prenatal diagnosis of Okihiro syndrome.

A case of Okihiro syndrome (OS) detected by 2- and confirmed by 3-dimensional ultrasound at 13+2 gestational weeks is reported. While the pregnant woman affected by the OS presented with limb anomalies, the fetus showed severe thoracoabdominal and skeletal anomalies. Termination of pregnancy was performed at 14+1 gestational weeks and confirmed the sonographically detected symptoms. The diagnosis was confirmed by autoptic, radiologic and molecular genetic analysis. To our knowledge, this is the first case of prenatal diagnosis of OS.

10p11.2 to 10q11.2 is a yet unreported region leading to unbalanced chromosomal abnormalities without phenotypic consequences.

Directly transmitted unbalanced chromosomal abnormalities (UBCA) or euchromatic variants (EV) were recently reported for >50 euchromatic regions of almost all human autosomes. UBCA and EV are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. Here we report on partial trisomies of chromosome 10 within the pericentromeric region which were detected by standard G banding. Those were referred for further delineation of the size of these duplicated regions for molecular cytogenetics and/or array-CGH. Partial trisomies of chromosome 10 in the pericentromeric region were identified prenatally in seven cases. A maximum of three copies of the region from 10p12.1 to 10q11.22 was observed in all cases without apparent clinical abnormalities. The imbalances were either caused by a direct duplication in one familial case or by de novo small supernumerary marker chromosomes (sSMC). Thus, we report a yet unrecognized chromosomal region subject to UBCA detected in seven unrelated cases. To the best of our knowledge, this is the first report of a UBCA in the pericentromeric region of chromosome 10 that is not correlated with any clinical consequences.

Interphase M-FISH applications using commercial probes in prenatal and PGD diagnostics.

Early, rapid and reliable diagnosis is of first priority in prenatal medicine. The combination of specific sonographic markers (e.g. nuchal translucency) and biochemical parameters in maternal serum (e.g. free beta-human chorionic gonadotropin, pregnancy-associated plasma protein A), has already dramatically improved the sensitivity of non-invasive first trimester risk screening in pregnancy. In invasive prenatal diagnosis, in addition to well-established chorionic villi short-term culture, interphase multi-colour-fluorescence in situ hybridisation (M-FISH) on uncultured amnion cells has become a reliable tool for the rapid detection of fetal aneuploidies. Interphase M-FISH applications have enabled the diagnosis of selected chromosomal abnormalities in single cells and, therefore, have also become an important diagnostic tool for preimplantation diagnosis (PGD). The development of commercially available probe sets, in particular, has led to a broad use of interphase M-FISH in prenatal and PGD diagnosis.

Detailed screening for fetal anomalies and cardiac defects at the 11-13-week scan.

OBJECTIVE: To assess the diagnostic efficacy of the first-trimester anomaly scan including first-trimester fetal echocardiography as a screening procedure in a 'medium-risk' population. METHODS: In a prospective study, we evaluated 3094 consecutive fetuses with a crown-rump length (CRL) of 45-84 mm and gestational age between 11 + 0 and 13 + 6 weeks, using transabdominal and transvaginal ultrasonography. The majority of patients were referred without prior abnormal scan or increased nuchal translucency (NT) thickness, the median maternal age was, however, 35 (range, 15-46) years, and 53.8% of the mothers (1580/2936) were 35 years or older. This was therefore a self-selected population reflecting an increased percentage of older mothers opting for prenatal diagnosis. The follow-up rate was 92.7% (3117/3363). RESULTS: The prevalence of major abnormalities in 3094 fetuses was 2.8% (86/3094). The detection rate of major anomalies at the 11 + 0 to 13 + 6-week scan was 83.7% (72/86), 51.9% (14/27) for NT < 2.5 mm and 98.3% (58/59) for NT >or= 2.5 mm. The prevalence of major congenital heart defects (CHD) was 1.2% (38/3094). The detection rate of major CHD at the 11 to 13 + 6-week scan was 84.2% (32/38), 37.5% (3/8) for NT < 2.5 mm and 96.7% (29/30) for NT >or= 2.5 mm. CONCLUSION: The overall detection rate of fetal anomalies including fetal cardiac defects following a specialist scan at 11 + 0 to 13 + 6 weeks' gestation is about 84% and is increased when NT >or= 2.5 mm. This extends the possibilities of a first-trimester scan beyond risk assessment for fetal chromosomal defects. In experienced hands with adequate equipment, the majority of severe malformations as well as major CHD may be detected at the end of the first trimester, which offers parents the option of deciding early in pregnancy how to deal with fetuses affected by genetic or structural abnormalities without pressure of time.

Epignathus: always a simple teratoma? Report of an exceptional case with two additional fetiforme bodies.

We report on a case of a fetal epignathus combined with two fetus-like structures resembling acardius acranius. The anomaly was detected at 23 weeks of gestation and led to termination of pregnancy at 24 weeks. This is the first description of epignathus with parasitic fetuses detected prenatally. It shows that the boundary between fetal teratoma and multiple pregnancy in special cases may be difficult to define.

Comparative genomic hybridization based strategy for the analysis of different chromosome imbalances detected in conventional cytogenetic diagnostics.

Today, conventional cytogenetics (CC) is the main technique in routine genetic diagnostics for the analysis of genotype/phenotype correlations. Additionally, fluorescence in situ hybridization (FISH) has proven to be useful for the characterization of structural chromosome aberrations found in conventional cytogenetics. Comparative genomic hybridization (CGH) is a molecular cytogenetic FISH approach developed for the detection of genomic imbalances with cytogenetic resolution. CGH allows the genome-wide assessment of relative DNA copy number changes using extracted specimen DNA as a probe. We investigated the capacity of CGH in cases referred for conventional cytogenetic diagnostics for the detection of chromosome imbalances. Three different groups of conspicuous karyotypes after CC (intrachromosomal rearrangements, interchromosomal rearrangements, and additional marker chromosomes) in pre- and postnatal diagnostic cases were surveyed by CGH to characterize the underlying imbalances of chromosome segments. All together, we investigated more than 100 cases by CGH and validated the results with other molecular cytogenetic methods. Here we present eight of these cases in order to demonstrate our CGH based strategy to analyze chromosomal de novo rearrangements. CGH provided additional cytogenetic information to complement conventional cytogenetic investigations. Additionally, CGH refined the description of the aberrant chromosome segments allowing us to further characterize the underlying mechanisms involved.

High frequency of spontaneous translocations revealed by FISH in cells from patients with the cancer-prone syndromes ataxia telangiectasia and Nijmegen breakage syndrome.

The application of fluorescence in situ hybridization (FISH) using whole-chromosome paints (WCPs) is proving to be a very powerful technique for revealing chromosomal instability that, for the most part, has gone undetected by conventional cytogenetic analysis. We have analyzed the frequency of translocations in lymphocytes and lymphoblastoid cell lines from ataxia telangiectasia (AT) and Nijmegen breakage syndrome (NBS) homozygotes and heterozygotes using a three-color chromosome-painting technique (WCP 1, 2, 4). With this assay we were able to detect an increased frequency of spontaneous translocations in AT homozygotes (median, 18.47 +/- 10.82 translocations per 1,000 metaphase cells; 10 patients) and AT heterozygotes (median, 7.87 +/- 3.15 translocations per 1,000 cells; 7 patients), in comparison to controls (median, 2.26 +/- 1.75 translocations per 1,000 cells; 10 controls). Analysis of NBS homozygotes (median, 19.05 +/- 11.27 translocations per 1,000 cells; 5 patients) and NBS heterozygotes (median, 6.93 +/- 3.04 translocations per 1,000 cells; 6 patients) also showed an increased frequency of translocations in these patients compared to controls. The presence of such hitherto undetected chromosomal aberrations corroborate previous findings of spontaneous chromosomal instability in AT and NBS patients, as manifested by an increased rate of open breaks and rearrangements involving chromosomes 7 and 14. Moreover, we show that the degree of genomic instability in AT and NBS patients is even higher than previously established and that some AT and NBS heterozygotes evidence spontaneous chromosomal instability as well. These increased levels of nonspecific translocations could be an important risk factor for the development of malignancies in homozygotes and heterozygotes for ATM or NBS1 gene mutations.

Prenatal diagnosis of familial absent pulmonary valve syndrome: case report and review of the literature.

We report on a case of absent pulmonary valve syndrome in a woman with a history of one healthy child and one child with tetralogy of Fallot with absent pulmonary valve. The diagnosis was missed at the first ultrasound examination performed at 13 + 5 weeks of gestation and correctly diagnosed at 21 + 5 weeks. Re-evaluation of the ultrasound examination recorded at 13 + 5 weeks exhibited severe insufficiency of the pulmonary valve at this time. However, neither dilatation of the right and left pulmonary arteries nor asymmetry of the ventricles were present at that time. The pregnancy was terminated at 22 + 1 weeks of gestation when autopsy confirmed the diagnosis of absent pulmonary valve syndrome. Karyotyping of the fetus after termination of pregnancy revealed normal chromosomes. Echocardiography of the parents and the healthy sibling revealed normal results.

Functional hemizygosity of PAFAH1B3 due to a PAFAH1B3-CLK2 fusion gene in a female with mental retardation, ataxia and atrophy of the brain.

We report on the molecular characterization of a translocation t(1;19)(q21.3;q13.2) in a female with mental retardation, ataxia and atrophy of the brain. Sequence analysis of the breakpoints revealed an ALU:-repeat-mediated mechanism of recombination that led to truncation of two genes: the kinase CLK2 and PAFAH1B3, the gene product of which interacts with LIS1 as part of a heterotrimeric G protein complex PAF-AH1B. In addition, two reciprocal fusion genes are present. One expressed fusion gene encodes the first 136 amino acids of PAFAH1B3 followed by the complete CLK2 protein. Truncated PAFAH1B3 protein lost its potential to interact with LIS1 whereas CLK2 activity was conserved within the fusion protein. These data emphasize the importance of PAF-AH1B in brain development and functioning and demonstrate the first fusion gene apparently not associated with cancer.

Clinical variability of Larsen syndrome: diagnosis in a father after sonographic detection of a severely affected fetus.

Larsen syndrome shows a broad spectrum of clinical manifestation ranging from a lethal form of the disorder to a mild clinical expression with absence of major diagnostic features. Here we show that even intrafamilial manifestation may vary extremely to the point that Larsen syndrome in a father has been diagnosed only by typical sonographic features in an affected fetus.

The Fanconi anemia group E gene, FANCE, maps to chromosome 6p.

Fanconi anemia (FA) is a genetically heterogeneous autosomal recessive disease with bone marrow failure and predisposition to cancer as major features, often accompanied by developmental anomalies. The cells of patients with FA are hypersensitive to DNA cross-linking agents in terms of cell survival and chromosomal breakage. Of the eight complementation groups (FA-A to FA-H) distinguished thus far by cell fusion studies, the genes for three-FANCA, FANCC, and FANCG-have been identified, and the FANCD gene has been localized to chromosome 3p22-26. We report here the use of homozygosity mapping and genetic linkage analysis to map a fifth distinct genetic locus for FA. DNA from three families was assigned to group FA-E by cell fusion and complementation analysis and was then used to localize the FANCE gene to chromosome 6p21-22 in an 18.2-cM region flanked by markers D6S422 and D6S1610. This study shows that data from even a small number of families can be successfully used to map a gene for a genetically heterogeneous disorder.

Characterization of ATM gene mutations in 66 ataxia telangiectasia families.

Ataxia telangiectasia (AT) is an autosomal recessive disease characterized by neurological and immunological symptoms, radiosensitivity and cancer predisposition. The gene mutated in AT, designated the ATM gene, encodes a large protein kinase with a PI-3 kinase-related domain. In this study, we investigated the mutational spectrum of the ATM gene in a cohort of AT patients living in Germany. We amplified and sequenced all 66 exons and the flanking untranslated regions from genomic DNA of 66 unrelated AT patients. We identified 46 different ATM mutations and 26 sequence polymorphisms and variants scattered throughout the gene. A total of 34 mutations have not been described in other populations. Seven mutations occurred in more than one family, but none of these accounted for more than five alleles in our patient group. The majority of the mutations were truncating, confirming that the absence of full-length ATM protein is the most common molecular basis of AT. Transcript analyses demonstrated single exon skipping as the consequence of most splice site substitutions, but a more complex pattern was observed for two mutations. Immunoblot studies of cell lines carrying ATM missense substitutions or in-frame deletions detected residual ATM protein in four cases. One of these mutations, a valine deletion proximal to the kinase domain, resulted in ATM protein levels >20% of normal in an AT lymphoblastoid cell line. In summary, our results survey and characterize a plethora of variations in the ATM gene identified by exon scanning sequencing and indicate a high diversity of mutations giving rise to AT in a non-isolated population.

Localisation of a Fanconi anaemia gene to chromosome 9p.

Using homozygosity mapping in a large consanguineous family, we have localised to chromosome 9p a further gene for the autosomal recessive, genetically heterogeneous disease Fanconi anaemia (FA). This is the fourth of at least eight FA genes to be localised to a discrete chromosomal region. Previously localised genes are FAA, FAC and FAD. By analysis of assigned families we show that the gene localised to chromosome 9p is FAF, FAG or FAH, or a new FA gene, and refine the localisation to the 21 cM region between markers D9S1678 and D9S175.

Characterization of cell cycle checkpoint responses after ionizing radiation in Nijmegen breakage syndrome cells.

Nijmegen breakage syndrome (NBS), which in the past also has been classified as a variant of ataxia telangiectasia (AT), is characterized by cancer proneness and extreme sensitivity to ionizing radiation. We investigated the DNA damage responses of four independent primary NBS fibroblast cell lines. Following a low dose of ionizing radiation, p53 is mostly induced with slower kinetics and shows more transient induction in NBS fibroblasts. Nonetheless, this damage-induced protein appears biologically functional: unsynchronized and synchronized NBS cells show a G1 arrest after ionizing radiation as determined by bivariate flow cytometry. Neither an AT cell line nor a NBS cell line transformed with human papillomavirus genes E6 and E7 shows a G1 arrest. Furthermore, NBS cells show a normal G2 block, unlike that shown for AT cells. These data provide a cellular distinction between NBS and AT, thereby clearly separating the NBS from the AT syndrome.

Linkage studies exclude the AT-V gene(s) from the translocation breakpoints in an AT-V patient.

An 8-year-old girl with severe microcephaly of prenatal onset, borderline intelligence, defects of skin pigmentation, deficiency of both humoral and cellular immunity, a normal serum alpha-fetoprotein level and hypersensitivity to ionizing irradiation is described. Spontaneous chromosomal breakage in lymphocytes together with the clinical presentation led to the diagnosis of ataxia telangiectasia variant (AT-V). In addition, the patient carried a constitutional translocation of paternal origin: 46,XX,t(3;7)(q12;q31.3) pat. In subsequent linkage and haplotype studies in 12 AT-V families with microsatellite markers from each of the translocation breakpoint regions, we could clearly exclude the localization of an AT-V gene to these regions.