Implication of the cystic fibrosis transmembrane conductance regulator gene in infertile family members of Indian CF patients

Endocrine disorders and fertility and pregnancy: An update

It is estimated that more and more couples suffer from fertility and pregnancy maintenance disorders. It is associated with impaired androgen secretion, which is influenced by many factors, ranging from genetic to environmental. It is also important to remember that fertility disorders can also result from abnormal anatomy of the reproductive male and female organ (congenital uterine anomalies - septate, unicornuate, bicornuate uterus; acquired defects of the uterus structure - fibroids, polyps, hypertrophy), disturbed hormonal cycle and obstruction of the fallopian tubes resulting from the presence of adhesions due to inflammation, endometriosis, and surgery, abnormal rhythm of menstrual bleeding, the abnormal concentration of hormones. There are many relationships between the endocrine organs, leading to a chain reaction when one of them fails to function properly. Conditions in which the immune system is involved, including infections and autoimmune diseases, also affect fertility. The form of treatment depends on infertility duration and the patient's age. It includes ovulation stimulation with clomiphene citrate or gonadotropins, metformin use, and weight loss interventions. Since so many different factors affect fertility, it is important to correctly diagnose what is causing the problem and to modify the treatment regimen if necessary. This review describes disturbances in the hormone secretion of individual endocrine organs in the context of fertility and the maintenance of pregnancy.

The CFTR gene mild variants poly-T, TG repeats and M470V detection in Indian men with congenital bilateral absence of vas deferens

The aim of the study was to detect the frequency of the CFTR gene variants poly-T, TG repeats and c.1408A>G p.Met470Val (M470V) in Indian men with congenital bilateral absence of the vas deferens (CBAVD). Men diagnosed with CBAVD (n = 76), their female partners (n = 76) and healthy men from general population (n = 50) were recruited. Genomic DNA was isolated and the polymorphic regions of IVS9- c.1210-12T [5] and M470V were amplified using specific primers followed by Sanger's DNA sequencing. A statistically significant increase in the frequency of heterozygous IVS9- c.1210-12T [5] (39.4%) was observed in CBAVD men as compared to controls (14%). The allelic distribution of c.1210-12T [5], c.1210-12T [7] and c.1210-12T [9] in CBAVD men was 21%, 64.4% and 13% and that in healthy controls was 7%, 73% and 20% respectively. Longest TG repeat c.1210-34TG [13] was found in association with c.1210-12T [5] with an allelic frequency of 5.9% in CBAVD men. We found a significant association of c.1210-34TG [12]/c.1210-34TG [13] - c.1210-12[5] -V470 allele in CBAVD men. Twelve female partners harboured a heterozygous c.1210-12T [5] allele. The study emphasises the need to screen both partners for the polymorphisms M470V, poly-T, TG tract repeats in addition to population-specific known CFTR gene mutations.

Spectrum and distribution of CFTR gene mutations in asthma and chronic pancreatitis cases of North Indian population

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) gene accounts for an autosomal recessive condition called cystic fibrosis (CF). In the Indian subcontinent, CF and its related diseases are under-diagnosed by the medical community due to poor knowledge of the disease and its confounding diagnosis, and also due to poor medical facilities available for these patients, thus causing an increased infant mortality rate with a low life expectancy in general. The aim of the study was to document the spectrum and distribution of CFTR mutations in controls, asthma and chronic pancreatitis cases of North India.

METHODS

A total of 800 subjects including 400 controls, 250 asthma cases and150 chronic pancreatitis cases were analyzed for 6 mutations (F508del, G542X, G551D, R117H, W1282X, and S549N) and IVS8 Tn polymorphism.

RESULTS

Out of 800 subjects, 18% [asthma - 24% (n=250), CP - 29.33% (n=150) cases and controls - 9.3% (n=400)] were positive for heterozygous mutation, 0.8% of the (n=250) asthmatic cases (n=250) were homozygous for IVS8 T5 polymorphism while no subjects were found positive for W1282X mutation. T5 polymorphism was more common in asthmatic cases while F508del mutation in chronic pancreatitis cases. The carrier frequency of F508del, G542X, G551D, R117H, S549N and T5 was 0.015, 0.025, 0.02, 0.005, 0.005, and 0.022 respectively. The cumulative carrier frequency was 0.093.

CONCLUSION

CFTR mutations were underestimated in Indian population. The present study will serve in establishment of genetic screening and prenatal setup for Indian population.

Genetic and epigenetic factors: Role in male infertility

Genetic factors contribute upto 15%-30% cases of male infertility. Formation of spermatozoa occurs in a sequential manner with mitotic, meiotic, and postmeiotic differentiation phases each of which is controlled by an intricate genetic program. Genes control a variety of physiologic processes, such as hypothalamus-pituitary-gonadal axis, germ cell development, and differentiation. In the era of assisted reproduction technology, it is important to understand the genetic basis of infertility to provide maximum adapted therapeutics and counseling to the couple.

Molecular basis of cystic fibrosis disease: an Indian perspective

Cystic fibrosis is a common autosomal recessive disorder usually found in population of white Caucasian descent. Now it is well documented the presence of CF disease in India with the advancement of laboratory testing. As once it was thought non existence of this disease in our population. Most of the phenotype of CF disease was in accordance of western population. Genetic analysis of CFTR gene in Indian CF patients revealed that most common mutation was delta F508 mutation. However, it was less than Caucasian population. CFTR mutations are also a causative factor in the pathogenesis of male infertility due to obstructive azoospermia. There are two most common mutation viz. IVS8-T5 and delta F508 which are responsible for congenital absence of vas deferens in male infertility patients. Elevated levels of sweat chloride at two occasions along with the presence of two mutations in CFTR gene was gold standard method for diagnosis of CF disease. It is noteworthy here that due to magnitude of Indian population, the total CF disease load would be more than many European countries. Clinical data demonstrate the prevalence of both classical and genetic form of CF in India.