Common variable immunodeficiency, impaired neurological development and reduced numbers of T regulatory cells in a 10-year-old boy with a STAT1 gain-of-function mutation.

Recently, gain-of-function (GOF) mutations in the gene encoding signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis (CMC). This case report describes a 10-year-old boy presenting with signs of common variable immunodeficiency (CVID), failure to thrive, impaired neurological development, and a history of recurrent mucocutaneous Candida infections. Sequencing of the STAT1 gene identified a heterozygous missense mutation in exon 7 encoding the STAT1 coiled-coil domain (c.514T>C, p.Phe172Leu). In addition to hypogammaglobulinemia with B-cell deficiency, and a low percentage of Th17 cells, immunological analysis of the patient revealed a marked depletion of forkhead-box P3(+)-expressing regulatory T cells (Tregs). In vitro stimulation of T cells from the patient with interferon-α (IFNα) and/or IFNÉ£ resulted in a significantly increased expression of STAT1-regulated target genes such as MIG1, IRF1, MX1, MCP1/CCL2, IFI-56K, and CXCL10 as compared to IFN-treated cells from a healthy control, while no IFNα/É£-mediated up-regulation of the FOXP3 gene was found. These data demonstrate that the STAT1 GOF mutation F172L, which results in impaired stability of the antiparallel STAT1 dimer conformation, is associated with inhibited Treg cell development and neurological symptoms.

Detection of clonal aberrations by cytogenetic analysis after different culture methods and by FISH in 129 patients with Chronic Lymphocytic Leukemia.

There are only a few cytogenetic analysis (CA) studies that directly compare the novel cultivation technique using immunostimulatory CpG-oligonucleotide DSP30/interleukin-2 (DSP30/IL2) with other culture methods. Therefore, parallel cultures of peripheral blood of 129 chronic lymphocytic leukemia (CLL) patients were set up in unstimulated cultures, in the presence of pokeweed medium (PWM), and with DSP30/IL2. Furthermore, CA results were compared with data obtained by FISH. Clonal aberrations were observed by CA in 6% of the cases in unstimulated cultures, in 27% of the cases with PWM, and in 40% of the cases with DSP30/IL2. Some clonal aberrations were detected by CA only with one culture method. Using 3 different culture methods, clonal aberrations were detected in 41% of the cases by CA and in 71% of the cases by FISH. Altogether, 78% of the cases exhibited clonal aberrations discovered by CA and FISH. Also, CA detected clonal aberrations not targeted by FISH in 7% of the cases, and FISH identified clonal aberrations not detected by CA in 36% of the cases. Our study demonstrates that the combined use of CA with different culture methods together with FISH increases our knowledge of the genetic complexity and heterogeneity in CLL pathogenesis.

Chromosome aberrations in a large series of spontaneous miscarriages in the German population and review of the literature.

BACKGROUND: In a review of the literature in 2000 the different cytogenetic aspects of spontaneous miscarriages were well documented. This review also included the spontaneous miscarriage results of one large German study published in 1990. However, to our knowledge there are no new data on spontaneous miscarriages in the German population. Therefore, the aim of the present retrospective large study was to find out the incidence and types of chromosome aberrations in an unselected series of spontaneous miscarriages in the German population, and whether our more recent results were different to data published previously. In case of culture failure we implemented a quantitative fluorescent polymerase chain reaction (QF-PCR) for chromosomes 13, 18, 21, X and Y. RESULTS: In the present German retrospective study cytogenetic analysis (CA) was attempted on 534 spontaneous miscarriages between weeks 7 and 34 of gestation, being successful in 73% (390/534) of them. Two hundred and thirty-seven of the cases (61%, 237/390) were chromosomally abnormal. Trisomy was the most common chromosome aberration and accounted for 53% (125/237) of the aberrant karyotypes. A multiple aneuploidy was observed in 7% (17/237) of the aberrant karyotypes. Chromosomes 16, 22, 15 and 21 were found most frequently involved in aneuploidies. Fifty-four cases (23%, 54/237) with a polyploidy were found in the present study. Single unbalanced structural chromosome aberrations accounted for 4% (10/237) of the aberrant karyotypes. Eleven samples (5%, 11/237) displayed a variety of numerical and/or structural chromosome aberrations. One hundred and forty-four spontaneous miscarriages (27%, 144/534) failed to grow in culture. A total of 27 cases were analysed by QF-PCR for chromosomes 13, 18, 21, X and Y, being informative in all cases. CONCLUSION: In our German retrospective large study of spontaneous miscarriages, the incidence and types of chromosome aberrations by CA are within the reported range of other studies published previously before and after 2000. Therefore, we can conclude that cytogenetic aspects of spontaneous miscarriages have not changed over the years. Additionally 8 of 27 cases (30%) without cell growth showed a numerical chromosome aberration by QF-PCR. Therefore QF-PCR played an important role as a supplementary test when culture failure occurred.

Chromosome aberrations identified by cytogenetic analysis of the first two clones of cultured amniotic fluid cells compared with QF-PCR results.

We report on our experience of studying amniotic fluid cells by cytogenetic analysis (CA) of the first 2 clones. We investigated the incidence and types of chromosome aberrations detected by CA of 196 amniocenteses performed on pregnant women at high risk. Of these cases, 178 were analysed by QF-PCR (risk group A). The results were compared with the data obtained by CA of 1,263 amniocenteses carried out in patients with other indications. QF-PCR was used to investigate 1,030 of these cases (risk group B). The combined average turnaround time for a CA result of the first 2 clones in both risk groups was within 9 ± 2 days. The final CA results (≥6 clones) were obtained within 12 ± 4 days. In risk group A, CA was not possible in 2 cases due to cell culture failure. The foetal karyotype was abnormal in 13.8% of the cases by CA of ≥6 clones and in 13.5% of the cases by QF-PCR. Together, CA of ≥6 clones and QF-PCR detected chromosome aberrations in 14.8% of the cases. With the exception of 2 cases of in vitro culture failure and 1 case with low gonosomal mosaicism, CA of the first 2 clones detected all cases with chromosome aberrations. Five cases with clinically significant chromosome aberrations were not detected by QF-PCR. In risk group B, the foetal karyotype was found to be abnormal in 2.2% of the cases by CA of ≥6 clones and in 1.0% of the cases by QF-PCR. Together, CA of ≥6 clones and QF-PCR revealed chromosome aberrations in 2.2% of the cases. With the exception of 1 case with low gonosomal mosaicism, CA of the first 2 clones detected all other cases with chromosome aberrations. The majority of these cases were inherited chromosome aberrations. Eighteen cases with chromosome aberrations were not detected by QF-PCR. Based on our results, CA of ≥6 clones, together with QF-PCR as a first test, should be performed in all prenatal cases with abnormal ultrasound findings. In pregnancies with other indications, CA of the first 2 clones alone is sufficient to identify all clinically significant (and inherited) chromosome aberrations.

No significantly increased frequency of the inversion polymorphism at the WBS-critical region 7q11.23 in German parents of patients with Williams-Beuren syndrome as compared to a population control.

BACKGROUND: Typical Williams-Beuren syndrome (WBS) is commonly caused by a ~1.5 Mb - ~1.8 Mb heterozygous deletion of contiguous genes at chromosome region 7q11.23. The majority of WBS cases occurs sporadically but few familial cases of autosomal dominant inheritance have been reported. Recent data demonstrated the existence of the paracentric inversion polymorphism at the WBS critical region in 7q11.23 in some of the progenitors transmitting the chromosome which shows the deletion in the affected child. In parents having a child affected by WBS the prevalence of such a structural variant has been reported to be much higher (~25- ~30%) than in the general population (~1- ~6%). However, in these previously reported studies only a limited number of randomly selected patients and non transmitting parents of WBS patients were used as controls, but without specification of any clinical data. Therefore we have undertaken a German population-based molecular cytogenetic investigation. We evaluated the incidence of the paracentric inversion polymorphism at 7q11.23 analyzing interphase nuclei of lymphocytes using a three color fluorescence in situ hybridization (FISH) probe. RESULTS: FISH analysis was carried out on couples with a child affected by WBS as compared to a population sample composed of different normal individuals: Control group I: couples with two healthy children, control group II: couples with fertility problems, planning ICSI and control group III: couples with two healthy children and one child with a chromosome aberration, not involving region 7q11.23. The three color FISH assay showed that the frequency of the paracentric inversion polymorphism at 7q11.23 in couples with a child affected by WBS was 20.8% (5 out of 24 pairs) as compared to 8.3% (2 out of 24 pairs, control group I), 25% (4 out of 16 pairs, control group II) and 9.1% (1 out of 11 pairs, control group III), respectively (total 7 out of 51 pairs, 13.8%). The frequencies differed between the groups, but this was statistically not significant (p > 0.05, Fisher's test). CONCLUSION: Our results do not support the hypothesis that the paracentric inversion polymorphism at 7q11.23 is a major predisposing factor for the WBS deletion.

Mosaic and complete tetraploidy in live-born infants: two new patients and review of the literature.

Tetraploidy is a very rare finding in live-born infants. Nine infants with tetraploidy have been reported earlier. The phenotype is of variable severity and consists of prenatal and/or postnatal growth retardation, developmental delay, mental retardation, dysmorphic features, and skeletal and internal abnormalities. Here we present a girl aged 2 years and 7 months with a mosaic tetraploidy detected in lymphocytes, and a newborn boy with a complete tetraploidy, who died 30 h after birth. They both show growth retardation, microcephaly, developmental delay, and craniofacial dysmorphisms. The clinical features of 22 patients reported earlier are reviewed.

Inheritance of a t(13;14)(q10;q10) Robertsonian translocation with a low level of trisomy 13 mosaicism.

INTRODUCTION: Low level of trisomy 13 mosaicism is a rare condition. In the present report, we describe a case of a 19-month-old boy with poor feeding, poor weight gain, mild dysmorphic features, mild muscular hypotonia, and speech delay. DISCUSSION: Cytogenetic analysis on metaphases of lymphocytes revealed an 8% mosaic Robertsonian translocation trisomy 13 in the boy and a balanced Robertsonian translocation, 45,XX,der(13;14)(q10;q10), in his normal mother. Fluorescence in situ hybridization (FISH) on patient lymphocytes disclosed 4% of metaphases with a trisomy 13. The trisomy 13 mosaicism in metaphases could not be identified by interphase FISH. The percentage of three signals (4%) was within the standard deviation in diploid controls. Follow-up of the patient was performed at the age of 7 1/12 years, and in cells from buccal smear of the patient, trisomy 13 was detected in 11% of interphases analyzed that is a higher frequency. Uniparental disomy of chromosomes 13 and 14 were excluded in the boy, and therefore, his phenotypic abnormalities most likely were caused by the low level of trisomy 13 mosaicism. CONCLUSION: The detailed report of this patient described the infrequent occurrence of a low mosaic Robertsonian translocation trisomy 13. We suggest to study cases of low trisomy mosaicism preferentially using metaphase analyses rather than interphase FISH. Our case is helpful in further defining the phenotype of these patients.