A novel locus on 19q13 associated with autosomal-dominant macular dystrophy in a large Greek family.

OBJECTIVE: To describe the clinical features of and genetic locus associated with autosomal-dominant macular dystrophy (MCDR5) in a large Greek family. METHODS: 26 members of a single family underwent clinical examinations and venepuncture. A genomewide linkage scan using 400 microsatellite markers distributed with an average spacing of 10 cM throughout the human genome. RESULTS: 14 members of the study family exhibited clinical features of the disease including decreased central vision and macular abnormalities in the posterior pole of the retina. Analysis of loci known to be associated with macular dystrophy did not show positive linkage. A genomewide linkage scan showed linkage to chromosome 19q, with a two-point maximum LOD score of 5.809 at theta = 0 between the disease and marker locus D19S412. On the basis of recombination events, the disease interval was localised between markers D19S420 and D19S540 on chromosome 19q, at a span of about 3.8 cM, in an area known to contain 120 known genes/transcripts. Eleven of these genes/transcripts were sequenced, and no disease-causing mutation was identified. CONCLUSIONS: This study describes a new locus on 19q associated with autosomal-dominant macular dystrophy, designated as MCDR5. Additional study of other family members will be necessary to further narrow the interval and identify the responsible gene. The study of MCDR5 will aid in elucidation of the underlying pathogenic mechanisms for this and other macular diseases, including age-related macular degeneration.

Supernumerary marker chromosome 5 diagnosed by M-FISH in a child with congenital heart defect and unusual face.

We describe a female patient with a small supernumerary marker chromosome (sSMC) present in mosaic and characterized in detail by fluorescence in situ hybridization (FISH) using all 24 human whole chromosome painting probes, multicolor banding (MCB) and subcentromere specific multicolor FISH (subcenM-FISH). The sSMC was demonstrated to be derived from chromosome 5 and the karyotype of our patient was as follows: 47,XX,+mar.ish r(5)(::p13.2 approximately p13.3-->q11.2::) [60%]/46,XX [40%]. Partial trisomy for the proximal 5p and q chromosomal regions is a rare event. A critical region exists at 5p13 for the phenotype associated with duplication 5p. As far as we know, eight similar cases have been published up to now. We describe a new case which, to our knowledge, is the first characterized in such detail. The role of uniparental disomy (UPD) in cases of SMC is also discussed.

Origin of nondisjunction in trisomy 8 and trisomy 8 mosaicism.

Causes of chromosomal nondisjunction is one of the remaining unanswered questions in human genetics. In order to increase our understanding of the mechanisms underlying nondisjunction we have performed a molecular study on trisomy 8 and trisomy 8 mosaicism. We report the results on analyses of 26 probands (and parents) using 19 microsatellite DNA markers mapping along the length of chromosome 8. The 26 cases represented 20 live births, four spontaneous abortions, and two prenatal diagnoses (CVS). The results of the nondisjunction studies show that 20 cases (13 maternal, 7 paternal) were probably due to mitotic (postzygotic) duplication as reduction to homozygosity of all informative markers was observed and as no third allele was ever detected. Only two cases from spontaneous abortions were due to maternal meiotic nondisjunction. In four cases we were not able to detect the extra chromosome due to a low level of mosaicism. These results are in contrast to the common autosomal trisomies (including mosaics), where the majority of cases are due to errors in maternal meiosis.

Partial trisomy 17q22-qter and partial monosomy Xq27-qter in a girl with a de novo unbalanced translocation due to a postzygotic error: case report and review of the literature on partial trisomy 17qter.

Partial trisomy 17q22-qter is a rare but well-recognized clinical entity. We present a case of partial trisomy for the long arm of chromosome 17, which was detected in a female infant with severe psychomotor and somatic retardation, Stargardt disease, short limbs, and numerous minor anomalies. Differential chromosomal staining demonstrated an excess of genetic material on the long arm of the late replicating X chromosome. FISH and DNA polymorphism analysis showed that the extra material belonged to the distal part of the long arm of chromosome 17 and that there was a partial monosomy of the distal part of the long arm of the derivative X chromosome. The breakpoint regions of this translocation were identified by molecular analysis using polymorphic microsatellite markers on human chromosomes 17 and X. The origin of the abnormal X chromosome was found to be paternal, whereas the origin of the duplicated part of chromosome 17 was maternal. The unbalanced translocation between the paternal X and the maternal chromosome 17 is, therefore, suggested to be due to a postzygotic error.

Management and outcome of severe diabetic foot infections.

We evaluated the bacteriological and clinical efficacy of the combination of ciprofloxacin/clindamycin in severe diabetic foot infections and we tried to elucidate the relationship between the vascular status of the lower limbs and the outcome of these infections. Initial empirical antibiotic therapy with ciprofloxacin (300 mg/12 hrs IV) and clindamycin (600 mg/8 hrs IV) was administered in 84 hospitalized diabetics with severe lower limb infections. This treatment was continued only in cases with primary clinical improvement. The major endpoints of treatment were: cure, improvement and failure. Evaluation of the vascular status of the lower extremities was performed by high resolution imaging coloured ultrasonography, US-Doppler and TcPO2 measurements. Polymicrobial flora was found in 83% of the cases with an average 2.8 species per specimen. Osteomyelitis was detected in 58 % of the patients. After five days of IV administration of ciprofloxacin and clindamycin the response rate was 95.2%. After three weeks of therapy the clinical outcome was: cure 54.8%, improvement 23.8%, and failure 21.4%. The long term follow up (mean duration 16 months) revealed complete healing of the skin lesions in 63 patients (75%). Unfavorable prognostic factors for these infections were: ankle systolic blood pressure <50 mmHg or toe systolic blood pressure < 30 mmHg and TcPO2 < 20 mmHg. The side effects of the combination of ciprofloxacin/clindamycin were mild and there were no cases of pseudomembranous enterocolitis. The combination of ciprofloxacin/clindamycin was found to provide an excellent empirical as well as definitive treatment of severe diabetic foot infections. The evaluation of the vascular status and the severity of ischaemia of the lower limbs has a strong predictive value in the outcome of these infections.

Sister-chromatid exchange in highly purified human CD4+ and CD8+ lymphocytes.

Sister-chromatid exchange (SCE) frequencies were determined in human peripheral blood CD4+ and CD8+ T lymphocyte subpopulations which were rapidly and highly purified from pooled T lymphocytes by immunological methods. The purified lymphocytes were stimulated with phytohemagglutinin (PHA) for 4 days. CD4+ lymphocytes showed significantly higher SCE frequencies than autologous CD8+ lymphocytes when measured simultaneously after identical bromodeoxyuridine (BrdU) incubation times. Differences in SCE frequencies between CD4+ and CD8+ lymphocytes were also detected when mitomycin C (MMC) was added to the cultures. Higher SCE frequencies in CD4+ lymphocytes were associated with lower proliferating rate indices (PRI) as compared to autologous CD8+ lymphocytes. Abnormalities in CD4+ T lymphocyte function and number in peripheral blood have been observed in several diseases characterized by immunological disorders. Thus, our data may suggest a link between some immunological disturbances and abnormal SCE frequencies in T lymphocyte subsets.

Clinical and hemorheological effects of buflomedil in diabetic subjects with intermittent claudication.

BACKGROUND: Changes in blood rheology have been described in diabetes mellitus. Buflomedil, a vasoactive substance with hemorheological properties, has been widely used in the treatment of intermittent claudication. The aim of this study was to evaluate the effect of buflomedil on clinical and hemorheological parameters in subjects with type 2 diabetes and intermittent claudication. METHODS: Forty patients were randomly assigned to oral buflomedil or matching placebo for six months in a double-blind manner. Initial and absolute walking distances were assessed by a standard treadmill testing protocol. Erythrocyte deformability was estimated with a whole blood filtration technique. ADP- and collagen-induced platelet aggregation was assessed with an aggregation profiler. beta-thromboglobulin and platelet factor-4 were measured with radioimmunoassays. All tests were performed at baseline and after three and six months of treatment. RESULTS: A significant increase in the mean initial (71%) and absolute (68%) walking distance was achieved only in the buflomedil group. ADP- and collagen-induced platelet aggregation was significantly reduced in the buflomedil group, while no significant changes in erythrocyte deformability, beta-thromboglobulin and platelet factor-4 levels were noticed. However, beta-thromboglobulin levels increased significantly in the placebo group. CONCLUSIONS: These findings suggest the therapeutic efficacy of buflomedil in diabetic subjects with intermittent claudication. The inhibition of platelet aggregation and the influence on platelet activity exerted by the drug could play an important role in its clinical effect and may be of value in the treatment of such patients.

Hyperbrachycephaly, short face, midface hypoplasia, fusion of cervical vertebrae, radiolucent bone defects, and severe destruction of periodontium--a new syndrome: craniofaciocervical osteoglyphic dysplasia.

A patient with an unusual combination of findings, which do not fit in any of the known syndromes, is presented. The patient, a 24.5-year-old male of normal growth and intelligence, manifests craniofacial dysmorphism, radiolucencies in the skull and in the cervical vertebrae, progressive alveolar bone loss and fusion of cervical vertebrae. The young man does not exhibit any other systemic, hematological, biochemical, chromosomal or immunological abnormality, except for IgA deficiency.

ZrO2 three-unit fixed partial dentures: comparison of failure load before and after exposure to a mastication simulator.

This study evaluated the failure load of different zirconia-based all-ceramic fixed partial dentures (FPD) before and after artificial aging. Forty-eight zirconia frameworks for three-unit FPDs were fabricated using different manufacturing systems [(DCS), Procera (Nobel Biocare) and Cerec inLab (Sirona)], veneered using Vita VM9 (Vita Zahnfabrik) opaque ceramic and conventionally cemented on human teeth. The restorations were divided according to the system used for manufacturing the frameworks into three groups of 16 specimens each (DCS, Procera and Vita YZ-Cerec). Half of each group was artificially aged through dynamic loading and thermal cycling, whereas, the other half was not subjected to artificial aging. Subsequently, all specimens were loaded occlusally until fracture occurred using a universal testing machine. Pair-wise Wilcoxon rank tests were performed to test for differences in failure loads at a statistical significance level of 0.05. All specimens subjected to artificial aging survived with no failures. The median (IQR=x0.25-x0.75) failure loads (N) before and after artificial aging were, respectively, as follows: group DCS, 2131 (1948-2239) and 1797 (1590-2074); group Procera, 1684 (1615-1873) and 1394 (1275-1495); and group Vita YZ-Cerec, 1845 (1621-1923) and 1625 (1521-1747). No significant differences were found for comparisons between different groups before artificial aging. After artificial aging, group Procera showed significantly smaller values than group DCS (P=0.042). All tested restorations have the potential to withstand occlusal forces applied in the posterior region and can therefore represent interesting alternatives to replace metal-ceramic restorations. Further assessments are needed before recommending these restorations for daily practice.

Apolipoprotein E allele distribution in parents of Down's syndrome children.

BACKGROUND: An increased risk of Alzheimer's disease (AD) has been reported in young mothers of Down's syndrome (DS) probands. Allele epsilon4 of the apolipoprotein E (apoE) gene is a genetic susceptibility factor for AD. We examined the distribution of apoE alleles in people with DS and their parents. METHODS: We studied 188 Danish people with non-mosaic free trisomy 21 of known parental origin (determined by DNA polymorphism analysis), and their parents, chosen from a population-based study of DS, and compared the frequency of apoE alleles with a previously published Danish control sample. FINDINGS: In people with DS, there was no significant difference in apoE allele distribution compared with controls. The frequency of allele epsilon4 in the fathers (11.8%) was significantly lower than in controls (17.4%, p=0.02). The frequency of allele epsilon4 in the mothers (19.4%) was not significantly different from that of controls. Nevertheless, in young mothers with a meiosis II error, epsilon4 frequency was 30.0%, significantly higher than in older mothers with a meiosis II error (13.0%, p=0.03). INTERPRETATION: We suggest that apoE allele epsilon4 is a risk factor for meiosis II non-disjunction in young mothers, but the biological role of apoE in oocytes remains to be investigated.

Impaired erythrocyte deformability precedes vascular changes in experimental diabetes mellitus.

The effect of diabetes on the red blood cell (RBC) deformability and its association with histological vascular changes was investigated in 35 streptozotocin-induced diabetic Wistar rats in a 30-day experiment and compared to 10 controls. RBC deformability was significantly impaired in the diabetic rats on day 5 (p < 0.001) and continued to deteriorate until day 20. On the 20 (th) day, the diabetic rats were randomly divided into two groups (group A: insulin-treated; group B: non-insulin-treated). A slight, non-significant (p = 0.20) improvement in RBC deformability was noticed in the insulin-treated group. In vitro incubation of RBCs with insulin did not improve the acquired RBC rigidity in either diabetic group. In contrast, it caused a significant reduction in RBC-deformability in the controls. On day 30, histological examination of arterial specimens from various sites revealed moderate to significant thickening in medium- and small-size artery and arteriole walls in both diabetic groups, with no evidence of diabetes-related changes in large, elastic-type arteries. No vascular changes were noticed in nine diabetic rats that succumbed between days 10 and 15. The results of this study indicate that reduced RBC deformability is an early manifestation of abnormal blood rheology in experimental diabetes, and precedes the evolution of vascular changes.

FRAXA and FRAXE prevalence in patients with nonspecific mental retardation in the Hellenic population.

Mutations at FRAXA and FRAXE loci are due to expansions of a CGG trinucleotide repeat and are characterized by mental retardation. Here we report a pilot screening survey by means of cytogenetic and molecular methods of 433 unrelated retarded individuals and their parents of Hellenic origin coming from various parts of Greece and Cyprus. The purpose of the study was to estimate the frequency of FRAXA mutation in individuals with nonspecific mental retardation without family history and phenotypic stigmata in the Hellenic population. Five FRAXA-positive children (1.15%) were identified, of whom four were found to carry a full mutation and one a premutation. Furthermore we present preliminary data on a screening of FRAXE mutation frequency. We screened 257 male patients with nonspecific mental retardation, finding none positive for FRAXE mutation.

Exclusion of one pedigree affected by adult onset primary open angle glaucoma from linkage to the juvenile glaucoma locus on chromosome 1q21-q31.

A locus for autosomal dominant juvenile onset primary open angle glaucoma (POAG) was recently assigned to chromosome region 1q21-q31. In the present study, a large Greek family with autosomal dominant adult onset POAG was investigated using microsatellite markers. Exclusion of linkage of the adult onset POAG gene to the region D1S194-D1S191 was obtained in this pedigree. Therefore, the data provide evidence that juvenile and adult onset POAG are genetically distinct disease entities.

Audiological profile of the prevalent genetic form of childhood sensorineural hearing loss due to GJB2 mutations in northern Greece.

The present study describes the audiological profile of genetic hearing loss resulting from GJB2 mutations in northern Greece, as this represents the most frequent single cause of childhood sensorineural hearing loss. The 35delG mutation in homozygosity was detected in 27 of 107 patients (25.2%). The audiological profile is that of a profound or severe sensorineural hearing loss, with a sloping or flat configuration of the audiogram, mostly symmetrical, non-progressive and affecting more the higher frequencies. This profile underlines the importance of early identification and genetic family counseling leading to the future possibility of prevention of deafness.

Refining the primary open-angle glaucoma GLC1C region on chromosome 3 by haplotype analysis.

The GLC1C locus for primary open-angle glaucoma (POAG) is inherited as an autosomal dominant trait. This region on chromosome 3 is 11 cM long. DNA samples from members of a Greek and an American GLC1C family were obtained to determine whether additional typing of microsatellite markers in family members might narrow the region. GLC1C family members were evaluated clinically for POAG on the basis of open angles, intraocular pressures, cupping of discs, and visual fields. DNA samples from the Greek and Oregon GLC1C families were used to further refine the GLC1C region using microsatellite markers. A total of 22 affected members were identified in the two families. Common alleles for D3S3637 and D3S3612 were present in the disease haplotype from both families, suggesting that they may have a common founder. A newly diagnosed patient in the American family had a recombination in the distal portion of the GLC1C haplotype. This recombination narrows the GLC1C region from 11 to 4 cM.

Prelingual nonsyndromic hearing loss in Greece. Molecular and clinical findings.

Mutations in the gene encoding the gap-junction protein connexin 26 (GJB2) on chromosome 13q11 have been shown as a major contributor to prelingual, sensorineural, nonsyndromic deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations and is one of the most frequent disease mutations identified so far with highest carrier frequency of 3,5% in the Greek population. In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific PCR for the detection of the 35delG mutation. The 35delG mutation was found in 32.1% of the alleles in 173 unrelated cases of prelingual deafness: 50 homozygotes and 11 heterozygotes. Individuals heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene, which revealed R184P and 486insT mutations in single alleles. We conclude that the 35delG GJB2 mutation is responsible for one third of prelingual, sensorineural deafness in Greece, which is higher than the usually quoted 20% for Caucasian populations.