Detection of mutations in the CYP21A2 gene: genotype-phenotype correlation in Slovenian couples with conceiving problems.

The objective of this study was to compare the CYP 21A2 genetic profiles of couples with unexplained fertility problems (UFP) with genetic profiles of healthy controls (HCs). Furthermore, we analyzed associations between mutations in the CYP21A2 gene and various clinical and laboratory parameters. Allele-specific polymerase chain reaction (PCR) was used in 638 probands with UFP and 200 HCs. Statistic analysis with χ2 was used to study the association of mutations with infertility. The effect of mutations on particular clinical and laboratory parameters was assessed with the analysis of variance (ANOVA) test. With regard to the CYP21A2 gene, 0.6% of probands with UFP and 0.5% of HCs were positive for the c.290-13A/C>G mutation; 0.6% of probands with UFP and 1.5% of HCs were positive for the p.I172N mutation; there were no probands with UFP positive for the p.P30L mutation, whereas 0.5% of HCs were; and 0.2% of probands with UFP and 0.5% of HCs were found to have the p.V281L mutation. We found a significant association between c.290-13A/C>G mutation and the frequency of significant hormone deviations (χ2 = 6.997, p = 0.008). Similar association was also observed between the c.29013A/C>G mutation and the frequency of polycystic ovary syndrome (PCOS) (χ2 = 16.775, p = 0.000). Our findings indicate that no significant difference in the prevalence of CYP 21A2 mutations can be found in probands with UFP when compared with HCs without infertility history. The results also imply the significant association of the c.290-13A/ C>G mutation in the CYP21A2 gene, not only with the frequency of PCOS, but also with the frequency of significant hormone deviations.

MTHFR C677T and A1298C Genotypes and Haplotypes in Slovenian Couples with Unexplained Infertility Problems and in Embryonic Tissues from Spontaneous Abortions.

The objective of this study was to analyze the methylenetetrahydrofolate reductases ( MTHFR s) C677T and A1298C genotype distributions in couples with unexplained fertility problems (UFP) and healthy controls, and to analyze the genotype and haplotype distribution in spontaneously aborted embryonic tissues (SAET) using allele specific polymerase chain reaction (PCR) in 200 probands with UFP, 353 samples of SAET and 222 healthy controls. The analysis revealed a significant overall representation of the 677T allele in male probands from couples with UFP ( p = 0.036). The combined genotype distribution for both MTHFR polymorphisms was also significantly altered (χ (2) 21.73, p <0.001) although female probands made no contribution (χ (2) 1.33, p = 0.72). The overall representation of the 677T allele was more pronounced in SAET (0.5 vs. 0.351 in controls, p <0.001) regardless of the karyotype status (aneuploidy vs. normal karyotype). In addition, the frequencies of the CA and CC haplotypes were significantly lower than in the control group ( p = 0.021 and p = 0.001, respectively), whereas the frequency of the TC haplotype was significantly higher than in controls ( p <0.0001). The presented findings indicate that only male probands contribute to the association of MTHFR mutations with fertility problems in grown adults and demonstrate a high prevalence of mutated MTHFR genotypes in SAET.

Molecular diagnosis of PMP22 gene duplications and deletions: comparison of different methods.

Several techniques can be used to diagnose Charcot-Marie-Tooth disease type 1A (CMT1A) and hereditary neuro pathy with liability to pressure palsies (HNPP), but no technique combines simplicity with high sensitivity. Multiplex ligation-dependent probe amplification (MLPA) was applied to develop an efficient and sensitive test for the detection of duplication/deletion of the peripheral myelin protein 22 (PMP22) gene. The study sample included 70 probands that had each been previously analysed by fluorescence in situ hibridization (FISH) and the restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) assay, both of which detect a unique recombination fragment uniquely present in most patients with the duplication. A total of nine duplications and 19 deletions were detected in the 70 probands using MLPA, and there was 100% concordance between MPLA and FISH. A single duplication was missed by the RFLP-PCR assay, which accords with the lower sensitivity of this method. It is concluded that the MLPA allows accurate detection of PMP22 gene duplications/deletions and could be used for the molecular diagnosis of these two neuropathies.

Early renal insufficiency in a neonate with de novo partial trisomy of chromosome 10q.

Partial trisomy of the long arm of chromosome 10 is a well-defined but rare syndrome. Clinical features of this chromosomopathy are a distinctive dysmorphic appearance, developmental delay, growth retardation, and in some cases, abnormalities of the extremities and renal, cardiac and ocular anomalies. This report describes a neonate with symmetric growth retardation and multiple dysmorphic features, in whom chromosomal analysis revealed a partial trisomy of chromosome 10q with a monosomy of the 13q34 region. The phenotype shares many common features with previously published cases. In addition to the typical features, our case also shows renal hypoplasia with early renal insufficiency and some genital anomalies.

Partial Xp duplication in a girl with dysmorphic features: the change in replication pattern of late-replicating dupX chromosome.

In this paper we present the case of a girl at the age of 32 months with dysmorphic features, including general muscular hypotonia, developmental delay and mental retardation. The cytogenetic analysis revealed de novo partial duplication of Xp: 46,X,dup(X)(p11.23-->p22.33: :p11.23-->p22.33). To characterize the duplication, X painting, Kallman (KAL), yeast artificial chromosomes (YACs) and bacterial artificial chromosomes (BACs) covering Xp11.23-->Xp22.33 region were used. Selective inactivation of the abnormal X chromosome using HpaII digestion of the AR gene was evident. After BrdU incorporation the abnormal X was late-replicating in all lymphocytes examined. There was one peculiar exception observed: the break-point region was consistently early replicating. The replicating pattern of this region corresponded to the active X chromosome. Methylation pattern of late replicating X chromosome was studied also using antibodies against 5-methylcytosine. The pattern corresponded to the normally inactive X chromosome, with the exception of the previously observed break-point region which revealed an early replicating pattern with strong fluorescent signal, similar to the pattern of the active X chromosome. The observed phenomenon could lead to the abnormal phenotype of the patient, with some normally inactive genes of the break-point region escaping the inactivation process. The abnormal clinical findings could also be due to tissue-dependent differences in the inactivation pattern.

Hypomethylation of alphoid DNA and classical satellite DNA on chromosome 1, 9, 16 and Y in extraembryonic tissue.

The pattern of DNA methylation can be analyzed on methaphase chromosomes with fluorescein labeled antibodies against 5-methylcytosine. In human extraembryonic tissue lower overall intensity of immunofluorescence in centromeric chromosomal regions correspond to hypomethylation of the DNA when compared with normal human lymphocytes. Pericentromeric regions on chromosomes 1,9,16 and heterochromatin on chromosome Y, which reveal lower levels of immunofluorescence, are rich in classical satellite DNA type II and III. In our experiment methylation-sensitive restriction enzymes, alphoid and classical satellite DNA probes specific for chromosomes 1,9,16 and Y were used. Southern blot analysis on cells from extraembryonic tissue revealed different extent of hypomethylation in different chromosomal regions. Our results confirm overall and sequence-specific hypomethylation of DNA in cells from extraembryonic tissue in comparison with somatic cells.

A case of insertional translocation resulting in partial trisomy 16p.

This report concerns the case of a boy with partial trisomy 16p resulting from the insertional translocation of the short arm of chromosome 16 into the long arm of chromosome 1 in his father. He was referred for genetic testing because of mental retardation, short stature, microcephaly, seizures and multiple dysmorphic features. Chromosome analysis performed in the child demonstrated the presence of additional material in the long arm of chromosome 1. Paternal high resolution chromosome analysis and fluorescence in situ hybridisation revealed the following karyotype: 46,XY,ins(1;16)(q42;p13.1p13.3), while the karyotype of the boy is 46,XY,der(1),ins(1;16)(q42;p13.1p13.3)pat. This is the first reported case of partial trisomy 16p due to paternal insertional translocation.