Chromosomal abnormalities and Y chromosome microdeletions in infertile men with varicocele and idiopathic infertility of South Indian origin

Various factors cause spermatogenesis arrest in men and, in a large number of cases, the underlying reason still remains unknown. Little attention is paid to determining the genetic defects of varicocele-related infertility. The objective of our present study was to investigate the chromosomal abnormalities and Y chromosome microdeletions in infertile men of South Indian origin with varicocele and idiopathic infertility. Metaphase chromosomes of 251 infertile men with varicocele and unexplained infertility were analyzed using Giemsa-Trypsin-Giemsa (GTG) banding and fluorescence in situ hybridization (FISH). The microdeletions in 6 genes and 18 sequence-tagged-sites (STS) in the Yq region were screened using polymerase chain reaction (PCR) techniques. Out of 251 infertile men, 57 (22.7%) men were with varicocele, of which 8.77% were azoospermic, 26.31% were severely oligozoospermic, 21.05% were mildly oligozoospermic, and 43.85% were oligoasthenoteratozoospermic (OAT), and 194 (77.29%), with idiopathic infertility, of which 51% were azoospermic, 13.40% were severely oligozoospermic, 19.07% were mildly oligozoospermic, and 16.4% were with OAT. Genetic defects were observed in 38 (15.13%) infertile individuals, including 14 (24.56%) men with varicocele and 24 (12.37%) men with idiopathic infertility. The frequencies of chromosomal defects in varicocele and idiopathic infertility were 19.3% and 8.76%, respectively, whereas Y chromosome microdeletions were 5.26% and 3.60%, respectively. Overall rate of incidence of chromosomal anomalies and microdeletions in 251 infertile men were 11.5% and 3.98%, respectively, indicating a very significant higher association of genetic defects with varicocele than idiopathic male infertility. Our data also demonstrate that, among infertile men with varicocele, severely oligozoospermic and OAT men with varicocele have higher incidences of genetic defects than mildly oligozoospermic and azoospermic men

Chromosome inversions and a novel chromosome insertion associated with recurrent miscarriages in South India

The aim of the present study was to investigate the contribution of chromosomal abnormalities and the frequency of a particular type of aberration in couples of South Indian origin with recurrent miscarriages. A total of 160 couples with recurrent miscarriages were analyzed using Giemsa-Trypsin-Giemsa (GTG) banding and Fluorescence in situ hybridization (FISH) wherever necessary. Chromosomal abnormalities were detected in 18 individuals representing 11.25% of the samples analyzed. Present study describes majority of the cases with chromosome inversions found to be common among the referred couples. Among the abnormal karyotypes, we report for the first time an unique case of chromosome insertion in a woman with the karyotype 46,XX,ins(12;6)(q24.2;q23q25) associated with recurrent miscarriages. The overall incidence of abnormalities and the predominance of chromosome inversions indicates to physicians that routine chromosome analysis of infertile couples of South Indian origin should be essentially considered before the planning of Intra Cytoplasmic Sperm Injection (ICSI), and also the priorities for cytogenetic screening in individual cases should be established

Y chromosome microchimerism in female peripheral blood

Male DNA of recognized fetal origin can be detected in the maternal circulation many years after delivery. It is referred to as fetal microchimerism, and is thus a possible explanation for the existence of low-level Y chromosome mosaicisms. Employing the nested polymerase chain reaction (PCR) technique, Y-specific markers were investigated in 13 cases with abnormal sex chromosome and 31 normal women. Sex-determining region Y (SRY) sequences were detected in normal women with a male child, which reflects the existence of fetal progenitor cells in the maternal circulation. This was completely absent in normal women with a female child. Individuals with the Y chromosome showed amplification for Y-specific markers. Microchimerism of Y was noted in Turner phenotype cytogenetically investigated with marker chromosome, and in an individual with XX karyotype. False positive amplifications are possible in nested PCR reactions, but the same could also be true for routine PCR. However, in the absence of any identifiable factor that could contribute to the recurrence of spurious PCR amplifications, cases of therapeutic importance must be tested at least five times. In such situations, DNA from an additional tissue should also be used for nested PCR

Role of CYP17 and CYP19 polymorphisms in idiopathic recurrent miscarriages among South Indian women

Recent reports suggest the relevance of gene polymorphisms in predicting reproductive outcome. The present study was aimed at investigating the relationship between the 5' UTR polymorphism of CYP17, a tetranucleotide repeat and a trinucleotide deletion polymorphism in CYP19. A case-control-based study approach was used, which included 143 cases and 88 controls from the South Indian population. A PCR-sequencing based genotyping was used to ascertain the status of the individual. The A1, A2 allele frequencies of CYP17 among the cases were 72 and 28% while among the controls were 68 and 32% respectively (OR 1.21, 95% CI: 0.63-2.32). The 7/7 repeat of CYP19 was the predominant one with a distribution frequency of 55% in the cases and 58% in the controls. The deletion was observed in 39% of the cases and 36% of the controls (OR 1.14, 95% CI: 0.62-2.10). Minor genotypes when taken together represented at a higher frequency in cases than those in controls (13 against 2%, P-value: 0.006). No statistically significant association exists between the CYP17 and CYP19 trinucleotide deletion polymorphisms and the risk of idiopathic recurrent miscarriages among women from South India. However, larger repeat numbers of the tetra nucleotide (except the common 7/11 genotype) showed significant association at 95% level

Missense mutations in the BMP15 gene are associated with ovarian failure

Premature ovarian failure (POF) is an unexplained amenorrhoea (>6 months) with raised levels of gonadotropins (FSH>40 U/L) occurring before the age of 40 years. Recent studies have elucidated the role of oocyte derived growth factors (BMP15 and GDF9) in maintenance of folliculogenesis, granulosa cell (GC) proliferation and overall fertility. Our recently published work showed presence of two rare missense variants in the GDF9 gene associated with ovarian failure. The present case-control study has been structured to establish the role of BMP15 germline status associated with ovarian failure. Sequence analysis of the coding region of the BMP15 gene was carried out in a cohort of women with POF (n=133), primary amenorrhoea (n=60), and secondary amenorrhoea (n=9) compared with control females (n=197). This study revealed a total of 18 germline variants in the coding region of BMP15 gene, including 16 novel variants. These novel variants include one intronic variant, one 3' flanking variant, one silent variant, and 13 missense variants. Eleven missense variants were present only in cases with complete absence in the control females. The remaining two missense variants viz. c.308A>G (p.Asn103Ser) and c.788_789insTCT (p.Leu263_Arg264insLeu) were present both in the cases and in the controls. The c.788_789insTCT variant was significantly higher in primary amenorrhoea cases than in the controls (Fisher's exact test, P=0.034). Three frequent variants c.-9C>G, c.308A>G, and c.852C>T were chosen for haplotyping. The haplotype G-G-C was found to be significantly associated with ovarian failure (P=0.0075). In a nutshell, the BMP15 gene is highly associated with etiology of ovarian failure

Germline study of AR gene of Indian women with ovarian failure

Objective: Present study was designed for carrying out the mutational analysis of the entire Androgen receptor (AR) gene including two microsatellite (CAG)n, (GGN)n, promoter region in cases of premature ovarian failure (POF) and primary amenorrhea (PA). Design: Previous reports of AR knockout mice model showed POF phenotype, this draws an attention on the role of AR gene in the aetiology of POF for the case-control association studies in POF samples (n=133), PA samples (n=63) and control samples (n=200). Results: We identified six mutations including four novel mutations, i.e. c.636G>A, c.1885+9C>A, c.1948A>G, c.1972C>A, and two previously reported mutations, i.e. c.639G>A, c.2319-78T>G. Repeat length variation was noted in the two microsatellite regions CAG and GGN, located in the coding region of exon 1 at the N-terminal region of the AR gene. The CAG repeat length was homogenously distributed with the same frequency and no association among all cases and controls. The GGN repeat showed a significant association among the SS and SL allele with p=0.0231 and p=0.0476, respectively, among the POF/control samples. Conclusions: Thus, AR gene mutations may play a role in the genetic cause of POF. Identification of the underlying genetic alteration of the AR gene is important for a proper diagnosis of POF subjects

Genes governing premature ovarian failure

Premature ovarian failure (POF) is unexplained amenorrhoea ( > 6 months), increased FSH ( > 20 IU/l) and LH occurring before 40 years. Several genes are reported as having significance in POF, including genes governing regulation of the hypothalamic-pituitary-ovarian axis, but their role in ovarian physiology is not known. Deletions or translocations in Xq arm have been found to be associated with POF, assuming presence of ovarian-related genes but ovary-related function of these genes is unclear. Several researchers have suggested specific loci on Xq critical region, POF1 and POF2 and genes DIA, FMR1 and FMR2. The understanding of ovarian physiology, its regulation and genes involved is important to explain the causes of POF. Some genes coordinate development of germ cell to primordial stage, e.g. GDF9, BMP15 and NGF, while others regulate development of further stages, such as FSH and LH. Mutation in these genes may lead to female infertility and are likely to be candidate genes for POF. Recently, association between blepharophimosis-ptosis-epicanthus inversus syndrome type 1 and POF has emerged as a possibility. Galactosaemia is also shown to be important in POF due to toxic effects of accumulated galactose or downstream products. Thus, understanding the role of several genes can be used for the appropriate genetic diagnosis, research and in the clinical practice of POF

Paternally derived translocation t(8;18)(q22.1;q22)pat associated in a patient with developmental delay: Case report and review

The common cause of mental impairment and the wide range of physical abnormalities is balanced chromosome rearrangement. As such, it is difficult to interpret, posing as a diagnostic challenge in human development. We present a unique familial case report with the paternally inherited autosomal-balanced reciprocal translocation involving chromosomal regions 8q and 18q. The etiology of the translocation, i.e. 46,XX,t(8;18)(q22.1;q22) was detected by conventional high-resolution Giemsa–Trypsin–Giemsa-banding and fluorescence in situ hybridization techniques. The father was found to be the carrier of the chromosome defect and also the same was observed in the first female child referred with a history of delayed milestone development. However, the second female child showed normal 46, XX karyotype. This is the first report of reciprocal translocation involving 8q and 18q associated with the delayed milestone development. The reason likely may be due to the rearrangement of genetic material at these breakpoints having a crucial relationship and thus manifesting developmental delay in the progeny. Accordingly, this paper also shows genetic counseling discussion for the cause

Unique Case Reports Associated with Ovarian Failure: Necessity of Two Intact X Chromosomes

Premature ovarian failure is defined as the loss of functional follicles below the age of 40 years and the incidence of this abnormality is 0.1% among the 30–40 years age group. Unexplained POF is clinically recognized as amenorrhoea (>6 months) with low level of oestrogen and raised level of Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH > 20 IU/l) occurring before the age of 40. It has been studied earlier that chromosomal defects can impair ovarian development and its function. Since there is paucity of data on chromosomal defects in Indian women, an attempt is made to carry out cytogenetic evaluation in patients with ovarian failure. Cytogenetic analysis of women with ovarian defects revealed the chromosome abnormalities to be associated with 14% of the cases analyzed. Interestingly, majority of the abnormalities involved the X-chromosome and we report two unique abnormalities, (46,XXdel(Xq21-22) and q28) and (mos,45XO/46,X+ringX) involving X chromosome in association with ovarian failure. This study revealed novel X chromosome abnormalities associated with ovarian defects and these observations would be helpful in genetic counseling and apart from, infertility clinics using the information to decide suitable strategies to help such patients