Cytogenetic studies using various clastogens in two patients with Werner syndrome and control individuals

Summary Chromosome studies were performed on peripheral lymphocytes from two patients with Werner syndrome and two healthy control individuals to detect spontaneous and/or mutagen-induced chromosomal instability of this disease. Diepoxybutane, isonicotinic acid hydrazide, 4-nitro-quinoline-1-oxide, and bleomycin were used as standard clastogens. While the spontaneous frequency of chromosomal breakage was much higher in lymphocytes from both patients than in the control cells, the basic rate of sister chromatid exchange (SCE) was found to be in the control range. The sensitivity to clastogens of the patients' cells, however, was not substantially increased as compared with the controls if the degree of multiplication of the spontaneous breakage rate or SCE frequency was taken as the basis for comparison. No indication of a greater inhibition of proliferation by the clastogens in the patients' cells than in normal cells was observed using BrdU-labelled lymphocytes. Thus, the lymphocytes from both patients of the present study lacked essential features of the classical chromosome instability syndromes.     

Episphalosomic syndrome : a MCA syndrome ressembling Fanconi anemia, with increased baseline level of chromosome breaks but no hypersensivity to clastogens

We describe a child with facial dysmorphism (trigonocephaly, epicanthus, upturned nose, small ears), thumb hypoplasia, micropenis, jejunal atresia and moderate mental retardation with dysphasia. Cytogenetic workup revealed high spontaneous level of chromosomal aberrations (without specific pattern and no quadriradial figures) and borderline to absent hypersensitivity to mitomycin C, making a diagnosis of Fanconi anemia unlikely. The child described here shares similarities with a small number of previous reports. We suggest to refer to this entity as episphalosomic syndrome. Episphalosomic syndrome shows some clinical overlap with Fanconi anemia, but lacks its cytogenetic hallmark. The hematological complications of Fanconi anemia have not been reported in this entity.     

Spontaneous 6-thioguanine-resistant lymphocytes in Fanconi anemia patients and their heterozygous parents

Summary The incidence of spontaneous 6-thioguanine-resistant (TG^r) lymphocytes was studied in the peripheral blood collected from seven Fanconi anemia (FA) patients and five of their heterozygous parents using an autoradiographic or a lymphocyte cloning method. Five of the seven patients showed a significantly elevated incidence of TG^r lymphocytes as compared to age- and sex-matched healthy controls. There was, however, no difference between FA heterozygotes and controls. These results suggest some variability among the patients similar to those reported in clinical and cytogenetic investigations. The basis for the increase in TG^r cells in the patients is not known, but the inherent genomic instability reflected as increased frequencies of chromosomal aberrations is one possible explanation.     

Cytogenetic,clinical and genealogical analyses in a series of gonadal dysgenesis patients and their families

Summary 46 individuals, ascertained due to gonadal dysgenesis symptoms, were studied. 16 of them were 45, X and showed characteristics of Turner's syndrome. 15 proved to be chromosome mosaics and presented Turner's syndrome (12 cases), mixed gonadal dysgenesis (2) and gonadoblastoma (1). There were also 2 cases of pure gonadal dysgenesis and 13 patients with normal karyotypes. The clinical and genealogical data obtained from these individuals and their families were compared with 26 other series reported in the literature. Common malformations besides those related to sexual development are: short stature, abnormal nails, low implantation of hair, pigmented naevi, shield chest, short neck and cubitus valgus. Persons with 45,X karyotypes generally presented a more severe clinical picture than mosaics. The prevalence of twins is higher than expected among the patients' sibs in the cases reported here and in 3 of the 5 other series for which data are available.

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Zusammenfassung 46 Personen mit Symptomen der Gonadendysgenesie wurden untersucht. 16 von ihnen waren 45,XO und zeigten Symptome des Turner-Syndroms. 15 erwiesen sich als Chromosomenmosaiken; 12 von ihnen zeigten ebenfalls das Turner-Syndrom, 2 zeigten eine gemischte Gonadendysgenesie, während 1 Patient ein Gonadoblastom aufwies. Außerdem wurden 2 Fälle von einer Gonadendysgenesie und 13 Patienten mit normalem Karyotyp beobachtet. Die klinischen und genealogischen Daten von diesen Patienten und ihren Familien wurden mit denen aus 26 Literaturserien verglichen. Außer den Störungen der sexuellen Entwicklung sind die folgenden Mißbildungen häufig: Kleinwuchs, abnorme Nägel, niedrige Haargrenze, Pigmentnaevi, schildförmiger Torax, kurzer Hals, Cubitus valgus. Im allgemeinen zeigen Personen mit 45,XO-Karyotypen ein schwereres klinisches Bild als Mosaiken. Unter den Geschwistern der Patienten finden sich Zwillinge häufiger als erwartet; das gilt auch für 3 der 5 anderen Serien, für die Daten verfügbar sind.

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Née Suñé.     

Expanded phylogenetic and dating analyses of the apples and their relatives (Pyreae, Rosaceae)

Despite previous efforts to elucidate relationships within the Pyreae (Rosaceae), relationships among the major sub-lineages, generic limits, and divergence times have remained uncertain. The present study greatly expands phylogenetic analyses of the Pyreae by using a combination of 11 chloroplast regions plus nuclear ribosomal ITS sequences from 486 individuals representing 331 species and 27 genera. Maximum likelihood and bayesian analyses generally support existing generic boundary, although Sorbus, as previously circumscribed, is clearly non-monophyletic. Two significant conflicts were detected between the chloroplast and ITS phylogenies, suggesting that hybridization played a role in the origins of Micromeles and Pseudocydonia. In addition, we provide estimates of the divergence times of the major lineages. Our findings support the view that the major Pyreae lineages were established during the Eocene-Oligocene period, but that most of the modern diversity did not originate until the Miocene. At least five major, early Old World-New World disjunctions were detected and these vicariance events are generally most consistent with movement through the Beringia.     

Cytogenetic,FISH and DNA studies in 11 individuals from a family with two siblings with dup(21q) Down syndrome

A Spanish family has previously been described with two siblings with dup(21q) Down syndrome. The father has a normal karyotype. The mother has a microchromosome. Cytogenetic, fluorescence in situ hybridization and DNA studies have now been carried out on the family. Findings include that the mother has three different chromosome anomalies, viz. (1) a chromosome 22 with an unusual pericentromeric region that contains alphoid DNA from chromosomes 21/13 and chromosome 22, (2) an isochromosome 21p in the frequent cell line and (3) an isochromosome 21q in a rare second cell line. A possible explanation is that the mother developed from a zygote with trisomy 21 and that mitotic error in early development resulted in the formation of two cell lines with karyotypes of 47,XX,+i(21p) and 47,XX,+i(21q), respectively. The unusual chromosome 22 represents a hitherto undescribed chromosome anomaly and one possible explanation is a translocation of the short arms between chromosomes 21/13 and 22 in the ancestry of the family. The relationship between the unusual chromosome 22 and the isochromosome formation in the mother is not known. However, all three chromosome anomalies involve the alphoid DNA of chromosome 21/13, indicating that this is not a chance finding.     

Phylogenetic relationships between two rare acacias and their common, widespread relatives in south-western Australia

Knowledge of phylogenetic relationships betweentaxa is particularly valuable for conservationmanagement of threatened taxa in anevolutionarily diverse flora such as that foundin the south-west of Western Australia. Acacia sciophanes and A. lobulata aretwo threatened species that have restricteddistributions at the edge of the range of theirwidespread relatives, A. anfractuosa andA. verricula respectively. The phylogenyof these species pairs was investigated usingRFLP analysis of cpDNA. Both restricted specieswere shown to be phylogenetically distinct.Acacia sciophanes and A. anfractuosaare sister species and display the characteristics of a relatively recent evolutionary lineage. In comparison A. lobulata shows significant divergence from A. verricula and is not closely related to the species group in which A. verricula is placed. Acacia lobulataappears to represent an ancient lineage and ismost likely a relictual species. Acaciaverricula also has characteristics of a moreancient evolutionary lineage than A.sciophanes and A. anfractuosa. Ifpriority setting processes based onphylogenetic principles were to be applied tothese species A. lobulata would have thegreater biodiversity value for conservationmanagement.     

Characterization of a large group of individuals with huntington disease and their relatives enrolled in the COHORT study

Background

Careful characterization of the phenotype and genotype of Huntington disease (HD) can foster better understanding of the condition.

Methods

We conducted a cohort study in the United States, Canada, and Australia of members of families affected by HD. We collected demographic and clinical data, conducted the Unified Huntington''s Disease Rating Scale and Mini-Mental State Examination, and determined Huntingtin trinucleotide CAG repeat length. We report primarily on cross-sectional baseline data from this recently completed prospective, longitudinal, observational study.

Results

As of December 31, 2009, 2,318 individuals enrolled; of these, 1,985 (85.6%) were classified into six analysis groups. Three groups had expanded CAG alleles (36 repeats or more): individuals with clinically diagnosed HD [n = 930], and clinically unaffected first-degree relatives who had previously pursued [n = 248] or not pursued [n = 112] predictive DNA testing. Three groups lacked expanded alleles: first-degree relatives who had previously pursued [n = 41] or not pursued [n = 224] genetic testing, and spouses and caregivers [n = 430]. Baseline mean performance differed across groups in all motor, behavioral, cognitive, and functional measures (p<0.001). Clinically unaffected individuals with expanded alleles weighed less (76.0 vs. 79.6 kg; p = 0.01) and had lower cognitive scores (28.5 vs. 29.1 on the Mini Mental State Examination; p = 0.008) than individuals without expanded alleles. The frequency of “high normal” repeat lengths (27 to 35) was 2.5% and repeat lengths associated with reduced penetrance (36 to 39) was 2.7%.

Conclusion

Baseline analysis of COHORT study participants revealed differences that emerge prior to clinical diagnosis. Longitudinal investigation of this cohort will further characterize the natural history of HD and genetic and biological modifiers.

Trial Registration

Clinicaltrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00313495","term_id":"NCT00313495"}}NCT00313495     

Fanconi anemia protein, FANCG, is a phosphoprotein and is upregulated with FANCA after TNF-alpha treatment

Fanconi anemia (FA) is a genetic syndrome characterized by bone marrow failure, birth defects, and a predisposition to malignancy. At this time, six FA genes have been identified, and several gene products have been found to interact in a protein complex. FA cells appear to overexpress the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). We therefore examined the effects of TNF-alpha on the regulation of FA complementation group proteins, FANCG and FANCA. We found that treatment with TNF-alpha induced FANCG protein expression. FANCA was induced concurrently with FANCG, and the FANCA/FANCG complex was increased in the nucleus following TNF-alpha treatment. Inactivation of inhibitory kappa B kinase-2 modulated the expression of FANCG. We also found that both nuclear and cytoplasmic FANCG fractions were phosphorylated. These results show that FANCG is a phosphoprotein and suggest that the cellular accumulation of FA proteins is subject to regulation by TNF-alpha signaling.     

Congenital malformations and developmental disabilities in ataxia-telangiectasia, Fanconi anemia, and xeroderma pigmentosum families.

Heterozygous carriers of an ataxia-telangiectasia (A-T), Fanconi anemia (FA), or xeroderma pigmentosum (XP) gene may be predisposed to some of the same congenital malformations or developmental disabilities that are common among homozygotes. To test this hypothesis, medical records, death certificates, and questionnaires from 27 A-T families, 25 FA families, and 31 XP families were reviewed. Eleven XP blood relatives (out of 1,100) were found with moderate or severe unexplained mental retardation, a significant excess compared to the FA and A-T families (3/1,439). There were four microcephalic XP blood relatives and none in the FA or A-T families. In the A-T families, idiopathic scoliosis and vertebral anomalies were in excess, while genitourinary and distal limb malformations were found in the FA families. A-T, FA, or XP heterozygotes may constitute an important proportion of individuals at risk for specific malformations or developmental abnormalities.     

Dermatoglyphic fingerprint heterogeneity among individuals with nonsyndromic cleft lip with or without cleft palate and their unaffected relatives in China and the Philippines

Cleft lip with or without cleft palate (CL/P) is a common birth defect (birth prevalence ranging from 1/500 to 1/2,000) with a complex etiology. Traits potentially related to CL/P, such as dermatoglyphics, may reflect the genetic and epidemiologic heterogeneity observed in CL/P. Such phenotypic heterogeneity in dermatoglyphic patterns may account for some of the variability in previously reported associations of dermatoglyphics and CL/P. To test this hypothesis, we took dermatoglyphic prints from individuals with nonsyndromic CL/P (n = 460) and their unaffected relatives (n = 254) from the Philippines and China. For both samples three raters designated the patterns as arch, ulnar loop, radial loop, whorl, or "other." Chi-square analysis and standard ANOVA were used to investigate heterogeneity between Filipino and Chinese study subjects. The significant associations between particular pattern types and CL/P were not the same in both populations, demonstrating population-specific association of CL/P and dermatoglyphic pattern types. The ANOVA of pattern type included both CL/P cases and their relatives, with affection status, sex, and population group as variables. For each pattern type except arches, population was significant (p < 0.0001); for radial loops, affection status was additionally significant (p < 0.0001). When only CL/P cases were considered, population was again significant for the ulnar loop (p < 0.0001), whorl (p < 0.0001), and "other" (p = 0.0002) patterns. The ANOVAs demonstrate between-population heterogeneity in dermatoglyphic pattern types. These results support our hypothesis that population-specific associations and population heterogeneity in dermatoglyphic patterns exist for CL/P cases and their relatives.     

Damage control and its costs: BM failure in Fanconi anemia stems from overactive p53/p21

Despite having well-characterized disease-associated mutations, the mechanisms underlying the progressive bone marrow failure and cancer susceptibility of Fanconi anemia have been unclear. In this issue of Cell Stem Cell, Ceccaldi et?al. identify an overactive p53/p21 stress response and cell cycle arrest as an underlying cause that starts during fetal development.