Transmembrane Conductance Regulator Gene Mutations Research Articles

Phenotypic impact of CFTR mutations on male reproductive tract agenesis in a Chinese cohort with congenital absence of the vas deferens.

To investigate the genotype-phenotype correlations of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and their impact on male reproductive tract development in a cohort of Chinese patients with congenital absence of the vas deferens (CAVD). A total of 121 Chinese CAVD patients underwent genetic testing for CFTR and ADGRG2 mutations, semen analysis, scrotal and transrectal ultrasound examinations, and reproductive hormone measurements. The genotype-phenotype correlations were analyzed, focusing on the impact of CFTR variants on the presence or absence of the epididymis, vas deferens, seminal vesicles, and other related structures. CFTR mutations were identified in 72.7% (88/121) of CAVD patients, with the IVS9-5T variant being the most prevalent (54.5%, 66/121). Six novel CFTR variants (CFTR: L218Ffs*15, V1007Ffs*40, V938M, A566V, S605P, H949P) were identified in Chinese men. Patients with CFTR homozygous IVS9-5T variants had a significantly lower rate of epididymal absence compared to those with one 5T and one non-5T variant or two non-5T variants (p = 0.016). Notably, patients carrying at least one non-5T variant were associated with an 8.17-fold increased risk of epididymal partial absence compared to those having the homozygous 5T mutation (95% confidence interval 1.52-59.58, p = 0.009). This study provides novel insights into the genotype-phenotype correlations of CFTR variants in Chinese CAVD patients, highlighting the differential impact of 5T and non-5T variants on male reproductive tract development. These findings provide additional information that may be helpful for genetic counseling, clinical management, and the development of personalized diagnostic and therapeutic strategies for CAVD patients.

Population Characteristics of the Spectrum and Frequencies of CFTR Gene Mutations in Patients with Cystic Fibrosis from the Republic of Bashkortostan (Russia).

Cystic fibrosis (CF) is one of the most common autosomal-recessive disorders worldwide. The incidence of CF depends on the prevalence of cystic fibrosis transmembrane conductance regulator gene (CFTR) mutations in the population, which is determined by genetic diversity and ethnicity. The search for the causes of mutations in the transmembrane conductance regulator gene (CFTR) was carried out using targeted next-generation sequencing (NGS) on the Illumina platform in patients with cystic fibrosis from the Republic of Bashkortostan (Russia), taking into account the ethnic structure of the sample. A total of 35 distinct causal variants were found in 139 cases from 129 families. Five (F508del, E92K, 3849+10kbC>T, CFTRdele2.3, L138ins) explain 78.7% of identified CF causal alleles. Variants N13103K and 394delTT were found in four families each. Variants 2143delT, S1196X, W1282X, Y84X, G194R, and 1525-1G>A, as well as the two previously described complex alleles-c. [S466X; R1070Q] and str.[G509D;E217G]-were found in two or three families each. Twenty additional variants occurred only once. Variant c.3883_3888dup has not been described previously. Thus, regional and ethnic features were identified in the spectrum of frequencies of pathogenic variants of the CFTR gene in the three major sub-groups of patients-Russians, Tatars, and Bashkirs. Taking into account these results, highlighting the genetic specificity of the region, a more efficient search for CFTR mutations in patients can be performed. In particular it is possible to choose certain test kits for quick and effective genetic screening before use of NGS sequencing.

Gut microbiota in adults with cystic fibrosis: Implications for the severity of the CFTR gene mutation and nutritional status

BackgroundMicrobial dysbiosis has been linked to cystic fibrosis (CF); however, the composition of gut microbiota in adult CF patients in relation to severity of CF transmembrane conductance regulator (CFTR) gene mutation and nutritional status have not yet been explored. Study aimed to assess the gut microbiota composition in adults with CF, and its relationship with the severity of CFTR mutations, and BMI. MethodsGut microbiota of 41 adults with CF, and 26 non-CF controls were compared using whole 16S rRNA gene sequencing. Differences in the microbial community between groups of patients classified according to the severity of CFTR mutations, and BMI were assessed. The alpha diversity, beta diversity, and taxa abundance were identified to reflect gut microbiota composition. ResultsResults showed a significant decrease in alpha diversity of bacterial communities in CF compared to non-CF group, but no significant difference between the CF groups distinguished by the severity of CFTR mutations. However, more severe mutations were associated with the higher relative abundance of Bacteroides and Streptococcus and the lower relative abundance of Faecalibacterium and Blautia. Undernourished CF patients showed significantly lower alpha diversity compared to non-CF group and CF patients with BMI within the norm. Significant differences in the structure of the gut microbiota between CF and non-CF groups, as well as between BMI groups were also found. ConclusionsOur research indicates that CF is associated with alterations in gut microbiota in adults. Additionally, in adult CF patients, the composition of the gut microbiota is also related to BMI.

Predicting weight gain in patients with cystic fibrosis on triple combination modulator.

Cystic fibrosis (CF) is caused by CF transmembrane conductance regulator (CFTR) gene mutations producing dysfunctional CFTR proteins leading to progressive clinical disease. Elexacaftor-tezacaftor-ivacaftor (ETI) remarkably improves lung disease but is associated with substantial weight gain. We performed a single-center longitudinal study predicting 6-month weight gain after ETI initiation. We used linear mixed effects modeling (LME) to determine association of ETI treatment with changing body mass index (BMI). Using linear regression, we examined BMI prediction models with distinct combinations of main effects to identify a model useful for patient counseling. We used up to eight commonly observed clinical characteristics as input variables (age, sex, percent predicted FEV1 [FEV1%], F508del homozygous state, pancreatic sufficiency, HgbA1c, prior modulator use and prior year number of pulmonary exacerbations). We evaluated 154 patients (19-73 years old, 54% female, FEV1% = 19-121, 0-6 prior year pulmonary exacerbations). LME demonstrated an association between ETI use and weight increases. Exhaustive testing suggested a parsimonious linear regression model well-fitted to data that is potentially useful for counseling. The two variable model shows that on average, BMI decreases by 0.045 (95% Confidence Interval [CI] = -0.069 to -0.021, p < 0.001) for every year of age and increases by 0.322 (CI = 0.142 to 0.502, p = 0.001) for each additional prior year exacerbation at the time of ETI initiation. Young patients with many prior year pulmonary exacerbations likely have the largest 6 month weight gain after starting ETI.

Cystic fibrosis transmembrane conductance regulator gene mutations in males with CBAVD versus nonobstructive azoospermia: A review

Cystic fibrosis transmembrane conductance regulator gene mutations in males with CBAVD versus nonobstructive azoospermia: A review

Frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in azoospermic Egyptian patients

Frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in azoospermic Egyptian patients

CFTR-Related Metabolic Syndrome: Genetic Variants Increasing Pancreatitis Risk in the Pediatric Puerto Rican Population

CFTR-related metabolic syndrome (CRMS) is a novel diagnosis due to widespread use of and advances in the newborn screening (NBS) process for cystic fibrosis (CF) in the United States of America, allowing for the diagnosis of asymptomatic children with CF. Before 2015, a large Puerto Rican pediatric population was not screened for CF in the NBS test. Studies have shown that patients presenting with idiopathic recurrent or chronic pancreatitis have an increased frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. We present a retrospective chart review of 12 pediatric cases (n = 12) that were presented to an outpatient community clinic with clinical manifestations associated with CF. The pancreatic insufficiency prevalence (PIP) score was calculated on CFTR mutations. The mutations considered for the calculation of the PIP score were: F508del (c.1521_1523del), V201M (c.601G > A), I507del (c.1519_1521del), and L1335P (c.4004T > C). V201M mutation was classified as mild in both PIP scores, and a correlation with pancreatitis was noted. Clinical manifestations vary in cases with the V201M variant (c.601G > A). One case was diagnosed with CFTR-related disorder (CRD) and recurrent pancreatitis. It is important to consider CRMS or CRD as a differential diagnosis in the pediatric population of Puerto Rico due to the implications and increased risk of pancreatitis and other CF-related complications.

Vitamin Status in Children with Cystic Fibrosis Transmembrane Conductance Regulator Gene Mutation.

The issue of vitamin metabolism in children with cystic fibrosis screen positive, inconclusive diagnosis (CFSPID) is not well known. The aim of this study was to determine the status of vitamins A, D, E, and C in the blood of a group of children with CFSPID. A total of 89 children were enrolled in the study (Me: 3.6 years, 52.8% boys), as follows: 28 with CFSPID, 31 with CF (cystic fibrosis), and 30 HC (healthy children). Their blood concentrations of vitamins A, D, E, and C, and their dietary intake of these vitamins were analysed in the study groups on the basis of a three-day food diary. The patients with CFSPID had significantly higher serum vitamin D (p = 0.01) and E (p = 0.04) concentrations, compared to the children with CF. None of the children with CFSPID revealed vitamin A or E deficiencies. Patients with CF had been consuming significantly higher vitamin D and E amounts (p = 0.01). The vitamin concentrations did not depend either on the pancreatic/liver function or on anthropometric parameters. In total, 32.14% of patients with CF did not cover the baseline recommended calorie intake, and 53.6% and 36% did not take the recommended vitamin E and vitamin A intake, respectively. Children with CF and CFSPID did not fully cover the dietary recommendations for vitamin supply, but vitamin deficiency was found only in CF.

Nutraceutical Approach to the Management of Cystic Fibrosis

Background: Cystic fibrosis (CF) is an autosomal recessive monogenic disease marked by a mutation in the cystic fibrosis transmembrane conductance regulator gene. Cystic fibrosis transmembrane conductance regulator gene mutations affect respiratory, digestive and reproductive functions and impede bicarbonate, bile acid, and sweat secretion. Moreover, the current trend indicates that CF is no longer only a paediatric disease, but has progressively become a disease that also affects adults. This calls for addressing the condition with an appropriate nutraceutical approach. Objective: The study aims to find and collate nutritional targets in the management of cystic fibrosis. Method: Studies highlighting the benefits of nutrients or nutraceuticals in the management of cystic fibrosis were included from previously published research articles (1971 to 2020). Data including nutrients, nutraceuticals, study design, study model, sample size, age, dose and duration of the dose of the supplement were extracted from the studies included and explored to understand their role. Results: About 26 studies were included in the present review. It was found that nutrient interventions comprising nutraceuticals, including dietary fibre, proteins and amino acids (taurine, arginine, glutathione), fats (medium-chain triglycerides, polyunsaturated fatty acids (omega-3 fatty acids), phytochemicals (apigenin, genistein, quercetin, curcumin, allicin, beta-carotene, Pulmonaria officinalis L, Epigallocatechin-3-gallate), micronutrients, including vitamin A, vitamin D, vitamin K, magnesium and zinc in addition to antioxidants exhibit improvement in the symptomatic condition of cystic fibrosis patients. Conclusion: The advent of nutraceuticals in the food industry and studies indicating their promising benefits have paved a path for targeted therapies in cystic fibrosis.

Surface Hydration Protects Cystic Fibrosis Airways from Infection by Restoring Junctional Networks.

Defective hydration of airway surface mucosa is associated with recurrent lung infection in cystic fibrosis (CF), a disease caused by CF transmembrane conductance regulator (CFTR) gene mutations. Whether the composition and/or presence of an airway surface liquid (ASL) is sufficient to prevent infection remains unclear. The susceptibility to infection of polarized wild type and CFTR knockdown (CFTR-KD) airway epithelial cells was determined in the presence or absence of a healthy ASL or physiological saline. CFTR-KD epithelia exhibited strong ASL volume reduction, enhanced susceptibility to infection, and reduced junctional integrity. Interestingly, the presence of an apical physiological saline alleviated disruption of the airway epithelial barrier by stimulating essential junctional protein expression. Thus, rehydrated CFTR-KD cells were protected from infection despite normally intense bacterial growth. This study indicates that an epithelial integrity gatekeeper is modulated by the presence of an apical liquid volume, irrespective of the liquid’s composition and of expression of a functional CFTR.

Occurrence of Cystic Fibrosis Transmembrane Conductance Regulator Gene Mutations in Patients with Allergic Bronchopulmonary Aspergillosis Complicating Asthma.

Whether cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations contribute to the high prevalence of allergic bronchopulmonary aspergillosis (ABPA) in India remains unknown. We aimed to evaluate the occurrence of CFTR mutations in subjects with ABPA complicating asthma. We sequenced the CFTR gene using genomic DNA from blood on the Illumina NextSeq500 platform. Before undertaking zygosity analysis by genome analysis toolkit, the known or novel single nucleotide polymorphisms (SNPs) and indels were called. For rigorous analysis, we included only high-quality SNPs (scores > 500) and coverage ranging from 30 × 150x. We included 18, 12, and eight adult participants of ABPA, asthma, and healthy controls, respectively. The frequency of SNPs was higher in asthmatic subjects than ABPA or healthy controls, albeit not statistically significant (9/12 [75%] vs. 11/18 [61.1%] vs. 3/8 [37.5%], p = 0.24). Of the 38 subjects, 23 yielded 50 variants (healthy controls [n = 5], ABPA [n = 22], asthma [n = 23]) corresponding to six SNPs not previously linked with ABPA. Of these, four SNPs (rs213950, rs200735475, rs1800113, and rs1800136) were catalogued in the NCBI database. We identified two novel SNPs (chr7:117250703, chr7:117282655) in four (ABPA [n = 1], asthma [n = 3]) subjects without corresponding reference SNP. Most SNPs (85.5%) were heterozygous. The frequency of SNPs was higher in ABPA subjects with high-attenuation mucus (52.2%) and bronchiectasis (39.1%) than serological ABPA (8.7%). Our study suggests the role of CFTR mutations in the pathogenesis of ABPA. The SNPs in the CFTR gene may contribute to disease severity in ABPA. Larger studies are required to confirm our findings.

Mutations in CFTR genes are associated with oligoasthenospermia in infertile men undergoing IVF

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation has been clearly defined in congenital absence of the vas deferens (CAVD), which is an important cause of obstructive azoospermia. However, the association between oligoasthenospermia and CFTR gene mutation remains controversial. To confirm this issue, 151 infertile Chinese men were screened for CFTR mutation by NGS approach, including 18 CAVD patients, 72 patients with severe oligoasthenospermia and 61 controls with normal sperm parameters. Frequency of mutation in exons of CFTR gene were 66.7% in CAVD patients (12/18) (p<0.001) and 8.33% in severe oligoasthenospermic patients (6/72) (p<0.05), both of which were significantly more frequent than that in the controls (0/61). In terms of introns mutation of CFTR gene, there was no significant difference in frequency of 5T between oligoasthenospermic men (5/144, 3.47%) and the controls (4/122, 3.28%) (p=0.645). In addition, 6 novel mutations in exons of CFTR gene in this study (c.3736A>G, c.635T>G, c.482delA, c.1858C>T, c.2042A>T, c.1586A>C) have not been reported in the Cystic Fibrosis Mutation Database before. Thus, our study provides evidence that CFTR gene mutation may be the aetiology of severe oligoasthenospermia other than CAVD. It may be necessary to screen for CFTR mutations in men with severe oligoasthenospermia before receiving assisted reproductive technology.

Genetic Modifying Factors of Cystic Fibrosis Phenotype: A Challenge for Modern Medicine.

Cystic fibrosis (CF) is a monogenic autosomal recessive disease caused by cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. CF is characterized by a high phenotypic variability present even in patients with the same genotype. This is due to the intervention of modifier genes that interact with both the CFTR gene and environmental factors. The purpose of this review is to highlight the role of non-CFTR genetic factors (modifier genes) that contribute to phenotypic variability in CF. We analyzed literature data starting with candidate gene studies and continuing with extensive studies, such as genome-wide association studies (GWAS) and whole exome sequencing (WES). The results of both types of studies revealed that the number of modifier genes in CF patients is impressive. Their identification offers a new perspective on the pathophysiological mechanisms of the disease, paving the way for the understanding of other genetic disorders. In conclusion, in the future, genetic analysis, such as GWAS and WES, should be performed routinely. A challenge for future research is to integrate their results in the process of developing new classes of drugs, with a goal to improve the prognosis, increase life expectancy, and enhance quality of life among CF patients.

Analysis of Clinical Manifestations, Imaging Features, and Gene Mutation Characteristics of 6 Children with Cystic Fibrosis in China.

Objective To explore the clinical manifestations, imaging features, and gene mutation characteristics of 6 children with cystic fibrosis (CF) so as to improve the understanding and diagnosis awareness of CF in children and reduce the missed diagnosis and misdiagnosis. Methods The clinical manifestations, imaging, and gene mutation data of six children with CF were collected and retrospectively analyzed. Results Among the 6 cases of CF, there were 4 males and 2 females. Among the 6 children with CF, 5 cases presented with recurrent respiratory tract infection. Etiology suggested 3 cases of Pseudomonas aeruginosa and 2 cases of Staphylococcus aureus. 3 cases had pancreatic exocrine dysfunction, manifested as diarrhea and aliphatic diarrhea, of which 1 case had high lipase in blood examination, and pancreatic ultrasound showed rough and enhanced pancreatic echo, considering pancreatic cystic fibrosis. 2 cases of CF combined with pseudo-Bartter syndrome (PBS); 1 case involved only the biliary tract and started with cholestasis without other systemic involvement. In 2 cases of sweat test, sweat chloride ions were all >60 mmol/L. 3 cases underwent fiberoptic bronchoscopy, and a large number of sticky secretions were visible under the bronchoscopy. CT of the chest revealed thickening of the bronchial wall (3 cases), bronchiectasis (1 case), atelectasis (1 case), and thin bronchial lumen (2 cases). 1 patient was found to have small airway lesions and mosaic perfusion during follow-up. All 6 children with CF underwent genetic testing. A total of 12 CF transmembrane conductance regulator (CFTR) gene mutations were found, of which 4 mutations were not reported in the literature. Conclusion CF is a disease caused by CFTR mutation. The incidence of this disease in China is low, and the clinical manifestations have great differences. The main symptoms are respiratory symptoms. Some children have gastrointestinal symptoms and/or PBS, and some children only show a single systemic lesion.

Determination of Cystic Fibrosis Mutation Frequency in Preterm and Term Neonates with Respiratory Tract Problems.

Cystic fibrosis (CF) is an autosomal recessive disease. The genetic transition occurs with CF transmembrane conductance regulator (CFTR) gene mutation. We aimed to determine the frequency of CF mutations and also new mutations in the CFTR gene in neonates with respiratory distress. Newborn babies hospitalized due to respiratory distress were included in the patient group. The control group consisted of infants who had no respiratory distress. The CFTR genes of both groups were analyzed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. A total of 40 patients (20 in the patient group and 20 in the control group) were evaluated. The CFTR gene analysis was normal in 16 neonates in the patient group, whereas in others: A46D (c.137C>A) (n = 1), D1312G (c.3935A>G) (n = 1), R117H (c.350G>A) (n = 1), S1426P (c.4276T>C) (n = 1) heterozygotes were detected; CFTR gene analysis was normal at 14 neonates in the control group, whereas in others: E1228G (c.3683A>G) (n = 1), E217G (c.650A>G) (n = 1), E632TfsX9 (c1894_1895delAG) (n = 1), I807M (c.2421 A>G) (n = 2), S573F (c.1718C>T) (n = 1) heterozygotes were detected. There was no significant difference in the patient and control groups’ CFTR gene analysis (p = 0.340). This study demonstrates the importance of CFTR gene analysis in asymptomatic newborn infants for follow-up and early diagnosis of CFTR-related disorders. In this study, a c.1894_1895delAG (E632TfsX9) heterozygous mutation detected in the CFTR gene in an asymptomatic newborn infant, was first encountered in the literature.

CFTR gene mutation spectrum among 735 Iranian patients with cystic fibrosis: A comprehensive systematic review.

In this study, the spectrum and frequency of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations previously reported among Iranian cystic fibrosis (CF) patients have been reviewed and discussed. Using the keywords of Cystic Fibrosis, CF, CFTR, and Iran, along with their Persian equivalents, a comprehensive search was performed on the online databases. After applying the inclusion and exclusion criteria, 16 articles with an overall sample of 735 Iranian patients with CF, were included in this systematic review. A total of 101 different CFTR gene variants had been reported. The mutation of p.Phe508del (c.1521_1523delCTT) (21.22%) was the most frequent one among Iranian patients with CF. In conclusion, due to the fact that in many provinces of Iran no specific study has been done so far, it seems that the CFTR gene mutation spectrum in patients with CF from Iran is much wider.

Konjenital Bilateral Vas Deferens Yokluğu Olan Türk Hastalarda Genomik Kopya Sayısı Varyasyonları Analizi

Aim: Congenital Bilateral Absence of the Vas Deferens (CBAVD) is a developmental abnormality that causes infertility in males. According to the literature, up to 88% of CBAVD cases have at least one pathogenic Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) mutation. However, based on our previous data, this rate was 15.90% in Turkish patients with CBAVD. We aimed to identify genomic copy number variations (CNV) and candidate genomic regions which could related to the CBAVD in Turkish population.Methods: CNV analysis was performed in 19 Turkish CBAVD patients normal karyotypes and a wild type CFTR genotype. We suggested that the DAD1 gene may be a candidate gene related to CBAVD by reviewing online databases and analyzing CNV findings. Sanger sequencing of the DAD1 gene exons was performed in 22 patients.Results: We identified 11 CNVs that most likely related with the disease in nine of 19 (47.3%) patients. As the most common CNV, 14q11.2 deletions were detected in there (15.79%) of the patients. There was only DAD1 gene in the sharing genomic region of two of the 14q11.2 deletions. No sequence variation was detected in the DAD1 gene of the patients.Conclusion: The 14q11.2 chromosomal region and the DAD1 gene may be associated with CBAVD. Further studies are needed to indentify the contribution of CNVs and DAD1 gene to CBAVD etiology.

Quantification of Phenotypic Variability of Lung Disease in Children with Cystic Fibrosis.

Cystic fibrosis (CF) lung disease has the greatest impact on the morbidity and mortality of patients suffering from this autosomal-recessive multiorgan disorder. Although CF is a monogenic disorder, considerable phenotypic variability of lung disease is observed in patients with CF, even in those carrying the same mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene or CFTR mutations with comparable functional consequences. In most patients with CF, lung disease progresses from childhood to adulthood, but is already present in infants soon after birth. In addition to the CFTR genotype, the variability of early CF lung disease can be influenced by several factors, including modifier genes, age at diagnosis (following newborn screening vs. clinical symptoms) and environmental factors. The early onset of CF lung disease requires sensitive, noninvasive measures to detect and monitor changes in lung structure and function. In this context, we review recent progress with using multiple-breath washout (MBW) and lung magnetic resonance imaging (MRI) to detect and quantify CF lung disease from infancy to adulthood. Further, we discuss emerging data on the impact of variability of lung disease severity in the first years of life on long-term outcomes and the potential use of this information to improve personalized medicine for patients with CF.

Prevalence of congenital absence of vas deferens and related genetic factors among male infertilities: A systematic review

A systematic review was conducted to describe the prevalence of congenital absence of vas deferens (CAVD) and types of cystic fbrosis transmembrane conductance regulator (CFTR) gene mutation, Adhesion G-protein coupled receptor G2 (ADGRG2) mutation leading to CAVD among male infertilities aimed at providing comprehensive counseling in the treatment of male infertility. Information and data from eligible publications were searched and selected from the PubMed and Medline e-library from 2010 to 2020 by using 8 main keywords. The results showed that the prevalence of CAVD was approximately 0.1% in male and about 80% of congenital bilateral absences of the vas deferens (CABVD) patients had the CFTR mutation. These mutations were recessive gene abnormalities on the long arm of chromosome 7. Besides the mutation, recent researches showed the mutation of the ADGRG2 gene on X chromosome also led to CBAVD. It was approximately 10 - 20% of CBAVD and 60 - 70% of the congenital unilateral absence of the vas deferens (CUAVD) that was still not diagnosed genetically. In conclusion, the genetic consultation is necessary for CAVD patients before deciding to have a baby

Prevalence of Abnormal Karyotypes among Males with Non-obstructive Azoospermia and Severe Oligozoospermia: A Retrospective Study

Introduction: Chromosomal abnormalities are one of the important causes of male infertility. Numerical and structural chromosomal abnormalities are seen frequently in men with azoospermia and severe oligospermia. Other abnormalities include Y Chromosome Microdeletions (YCMD), Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene mutations affecting the internal ductal system, genes affecting sperm function and other non-specific disorders. Upto 14% of the men with azoospermia and severe oligospermia have karyotypic abnormalities. Aim: To determine the prevalence of abnormal karyotypes among men with azoospermia and severe oligozoospermia (&lt;5 million/mL). Materials and Methods: The present study was a retrospective observational study carried out at the Fertility Clinic, Institute of Maternal and Child Health, Calicut, Kerala, India, on patients who attended the Infertility Department between January 2016 to December 2019. Semen analysis was done on 232 patients with 100 patients of azoospermia and 132 patients of oligozoospermia. Karyotyping was done from the Cytogenetics Unit, Department of Anatomy. The data was entered in MS excel sheet and analysed and results were expressed in percentage. Results: Chromosomal abnormalities were detected in 35 (35%) of 100 azoospermia and 15 (11.3%) of 132 severe oligospermia cases analysed. Klinefelter syndrome was the most common abnormality detected in azoospermia (22/35). A 46XX was found in two cases. Structural abnormalities were detected in three case (46 X, der X, 46XY der Chr 1 and Chr 9 inversion). Small Y was found in three cases. Polymorphic variants were found in five patients (46XY 15pstk+, 46XY 15ps+, 46XY 1qh+, 46XY 9qh+). Small Y was found in one case. In oligozoospermia, autosomal translocations were found in four cases {46XY, t(11;13)(q21;q21.2), 46XY, t(1;9) (p13;p21), 46XY, t(13;15)(q34;q21), 46XY, t(7,14) (q34:q11)}, Derivative (46XY der 15) and Marker chromosome (47XY+mar) in one case each. Klinefelter syndrome was found in two cases and 48XXYY was found in one patient. Polymorphic variants were found in five cases (46XY 21pstk,46XY 15ps+, 46XY 1qh-, 48XY 9qh+). Small Y was found in one case. Conclusion: Sex chromosomal and autosomal abnormalities are found frequently in azoospermia and severe oligospermia and hence, genetic screening and counseling before Intracytoplasmic Sperm Injection (ICSI) is warranted.