First insights into the genetics of 21-hydroxylase deficiency in the Roma population.

Miscarriage is one of the major problems of modern reproduction. Total frequency of micarrieges is estimated as 15–27 % of total pregnancies. Recurrent Miscarriage (RM) (three or more spontaneous abortions) is responsible for almost 20 % of total miscarrieges. The population frequency of RM fluctuates from 2 % to 5 %. One of the important causes of abortion in the first trimester are hormonal disturbances in the mother, including adrenal hyperandrogenism, which results in congenital adrenal hyperplasia (CAH). In 95 % of cases, this pathology is caused by mutations in the 21-hydroxylase gene (CYP21A2), encoding for 21-hydroxylase. A non-classical form of CAH is the leading factor in 30 % of RM in women with hyperandrogenia. The aim of this study was to investigate the role of the most common mutations in the CYP21A2 gene in women with RM for more accurate diagnosis of this pathology. The level of 17-OH-progesterone was measured in women with RM and with mutations in the gene CYP21A2. The frequency of mutations in the CYP21A2 gene in RM women was significantly higher than in the group of women who don’t have these mutations (14.4 ± 3.3 % and 2 ± 1.4 %, respectively, p <0,05 df = 1). According to the odds ratio the risk of RM in CYP21A2 mutations carriers is 8 times higher than in the women without these mutations (OR = 8.4 (1.9–37.6)). The level of 17-OH-progesterone is not associated with mutations in CYP21A2 gene in the women with RM

Background Chronic kidney disease (CKD) poses a significant health challenge among patients, contributing to substantial morbidity and mortality outcomes. However, there remains a paucity of data within the medical literature on the Roma population, one of the most significant minority groups globally, with studies indicating that these individuals are disproportionately affected by CKD compared to the general population, with higher prevalence rates. Materials and methods We conducted an observational, cross-sectional study from October 2022 to March 2024, evaluating 735 adult patients with type 2 diabetes mellitus, of which 402 were Roma, aged 18 to 89 years, following the hospital's standard protocols for diabetes management, at the "Nicolae Malaxa" Clinical Hospital in Bucharest, Romania, a tertiary care center for diabetes. Results The prevalence of CKD was higher among the Roma patients, reaching 56.50% (n=203), in comparison with the Caucasian group (43.50%, n=156), however, with a lower mean age (55.53±10.56 years versus 63.32±10.04 years). Roma patients with CKD had a higher prevalence of cardiovascular disease compared to Caucasians, including myocardial infarction, stroke, stable angina, and heart failure. Cardiovascular risk factors, such as hypertension, obesity, and dyslipidemia, in patients with CKD, were also more prevalent among the Roma population. Taking into consideration the natural progression of CKD, the anthropometric measurements and laboratory parameters stratified by ethnicity revealed that Roma patients in the very high risk of CKD progression category had a lower mean age, and a lower median duration of diabetes (56.37±10.79 versus 59.92±7.48 years, and 4.00±2.00 versus 10.00±10.30 years, respectively), as well as a more elevated mean waist circumference (WC), body mass index (BMI), total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-c) compared to Caucasians. Moreover, patients in the very high risk of CKD progression category among both groups showed the highest level of insulin resistance, measured by the triglyceride-glucose (TyG) index (mean value of 10.13±0.60 among the Roma patients, and 10.09±0.82 among Caucasians). Among the study group, weight, WC, BMI, and A Body Shape Index (ABSI) were associated with a very high risk of progression of CKD. In Caucasian patients, it was demonstrated that weight, WC, BMI, ABSI, and triglycerides (TG) have contributed to the very high risk of progression of CKD, while among the Roma patients, no association was found. Conclusion In conclusion, our findings suggested a high prevalence of CKD among both groups. There is still a need for further investigation of additional risk factors, such as genetics, limited access to health education, and appropriate treatments that could synergistically accelerate the progression of CKD among Roma patients.

Congenital Adrenal Hyperplasia (CAH) is one of the highly prevalent autosomal recessive endocrine disorders. The majority of CAH cases result from mutations in the CYP21A2 gene, leading to 21-hydroxylase deficiency. However, with the pseudogene-associated challenges in CYP21A2 gene analysis, routine genetic diagnostics and carrier screening in CAH are not a part of the first-tier investigations in a clinical setting. Furthermore, there is a lack of data on the carrier frequency for 21-OH deficiency. Therefore, this study is aimed at investigating the carrier frequency of common pseudogene derived CYP21A2 mutations in Southern India. Recently, a cost-effective Allele-specific PCR based genotyping for CYP21A2 hotspot mutations has been demonstrated to be a highly specific and sensitive assay at the authors' center. Leveraging this approach, a total of 1034 healthy individuals from South India underwent screening to identify the carrier frequency of nine hotspot mutations in the CYP21A2 gene. In this study, it was observed that 9.76% of the subjects were carriers for one or more of the nine different CYP21A2 mutations. Among the carriers, the most common was the large 30 kb deletion, followed by II72N, E6 CLUS, and I2G mutations. We have identified a high prevalence of CYP21A2 mutation carriers in Southern India. These findings emphasize the importance of implementing and expanding cost-effective genetic diagnostics and carrier screening throughout India. Such initiatives would play a crucial role in managing the disease burden, enabling early intervention, and establishing guidelines for CAH newborn genetic screening in the country. This study represents the first carrier screening data on CYP21A2 hotspot mutations from India and is the largest study conducted till date in this context.

Objective To analyze the correlation of clinical phenotype and genotype and gene mutation frequency characteristics of 21-hydroxylase deficiency, and to provide the basis for clinical diagnosis and methods for early intervention. Methods The clinical phenotypic signs and examination results of 14 cases with 21-hydroxylase deficiency were collected from September 2008 to December 2016 in Children′s Hospital of Shanxi Province.Point mutations, deletions and conversion mutations for gene CYP21A2 coding 21-hydroxylase were detected through using next generation sequencing(NGS) and multiplex ligation-dependent probe amplification(MLPA). The captured mutations were further confirmed with Sanger sequencing.Furthermore, the family members underwent the co-segregation validation through the Sanger sequencing or MLPA in those captured mutated sites. Results Among the total 14 cases, 9 cases were identified as the salt wasting, 5 cases the simple virilizing; 10 cases of compound heterozygous mutations, and 4 cases of homozygous mutations.Analysis of the 14 patients revealed 8 different kinds of mutations in CYP21A2 gene.The most frequent mutations of CYP21A2 gene were I2G [50%(14/28)] and I173N [21.4%(6/28)], followed by Arg357Trp[10.7%(3/28)]. Del[10.7%(3/28)] mutations including E247fs, Gly111fs and R484fs.Q319X[3.6%(1/28)] and Arg355His[3.6%(1/28)] were rarely found.Missense mutation was found in 10 cases, splicing mutation in 14 cases, frameshift mutations in 3 cases, nonsense mutations in 1 case.All of the mutations were inherited from their parents, and no new mutation was found.The most common mutations for salt wasting and simple virilizing were respectively I2G[50%(9/18)] and I173N [50%(5/10)]. Collectively, genotypes and phenotypes were matched with each other. Conclusions The combination of clinical phenotypes with laboratory examination by gene sequencing and comprehensive analysis, is helpful to early diagnosis, differential diagnosis and optimized treatment, which will improve prognosis and provide guidance for genetic consultancy. Key words: Congenital adrenal hyperplasia; 21-hydroxylase; Mutation; Next generation sequencing

Summary: Introduction: Slovakia is a country with the highest prevalence of liver cirrhosis in the world and a country with the highest proportion of Roma ethnicity at the same time. However, there is only little evidence of Roma representation in national cohorts with cirrhosis. Aims: 1. To determine the prevalence of Roma ethnicity in our cirrhosis and liver transplant registers; to compare their 2. fundamental characteristics and 3. final results with patients from the majority population. Patients and methods: A retrospective study; we acquired data from 1. Cirrhosis registry RH7; 2. Liver transplant registry: a) patients listed active on the liver-transplant waiting list; b) patients underwent first LT. The first source – the cirrhosis registry RH7 (NCT 04767945; since 2014, RH7 has been listing consecutive patients admitted to hospital with liver cirrhosis). Up to 2021, the mode of the ethnicity determination was so-called “ascribed ethnicity”. The second source – the Liver transplant registry (since 2008); the mode of ethnicity determination was identical to the one of RH7. Apart from the ethnicity, the following points were recorded and analyzed in all patients: demographics, elementary cirrhosis-relevant clinical variables such as etiology and MELD score, as well as an elementary LT-relevant variables, such as waiting time and mortality. Results: We present the results on Roma ethnic group in three cohorts from two datasets, i.e. on 1,515 patients from RH7, on 464 waitlisted patients from LT registry and on 302 transplanted patients from LT registry, respectively. The representation of Roma ethnicity in these cohorts were 2%, 4%, and 4%, respectively. Significant differences in age and gender were detected in Roma cirrhotic patients: 46 vs. 55 years (P = 0.001) and female gender 25% vs. 39% (P = 0.042). Of the first time waitlisted candidates for LT, Roma patients were also significantly younger – 42.6 vs. 51.5 years; in addition, Romas had a less prevalent alcohol-associated etiology (ALD) and a more prevalent autoimmune etiology. Finally, Roma patients after first LT were younger – 40.2 vs. 51.6 years, again with lower etiology of ALD – 15% vs. 47% and more autoimmune etiology – 39% vs. 23%. The results of Romas from all cohorts in tertiary care were comparable. Conclusion: 1. the admission of Romas to a tertiary liver care is lower than expected, for unknown reasons; 2. the age of Romas entering tertiary care is approximately ten years lower; 3. the results of Romas in tertiary care is comparable to the majority population. Key words: liver cirrhosis – Roma ethnicity – tertiary liver care – waiting list – liver transplantation

Steroid 21‐hydroxylase deficiency (21OHD) accounts for approximately 95% of cases of congenital adrenal hyperplasia, one of the most common inherited metabolic disorders. It can be clinically classified into classic and nonclassic 21OHD. Classic 21OHD is associated with glucocorticoid deficiency and, in 46,XX patients, with disorder of sex development. Mineralocorticoid synthesis may also be significantly impaired in two‐thirds of patients, leading to life‐threatening salt‐wasting (SW) crises. Nonclassic 21OHD is milder and presents mainly with hyperandrogenism. 21OHD is caused by mutations in the CYP21A2 gene. The vast majority of CYP21A2 mutations are a result of unequal crossing overs and gene conversions with its highly homologous pseudogene, CYP21A1P . Molecular genetic analysis is challenging and requires the combination of different methods to detect gene deletions, chimeric genes, gene duplications and point mutations. An overall good genotype–phenotype correlation exists for the SW phenotype. Therefore, molecular diagnosis of 21OHD complements clinical diagnosis and allows for clinical and genetic counselling. Key Concepts: Steroid 21‐hydroxylase deficiency (21OHD) is an autosomal recessive disorder caused by mutations in the CYP21A2 gene and represents the most common form of congenital adrenal hyperplasia. A good genotype–phenotype correlation exists for the mineralocorticoid deficiency phenotype. Although a trend exists, the severity of 46,XX disorder of sex development as well as of other hyperandrogenic signs and symptoms correlates less strongly with the CYP21A2 genotype. Common pseudogene‐derived mutations account for the majority of 21OHD disease‐causing alleles; these include gene deletions, chimeric genes, seven single point mutations, an 8 base‐pair deletion and a cluster of three point mutations. Molecular genetic analysis of the CYP21A2 gene is challenging due to the high‐sequence homology with its pseudogene ( CYP21A1P ), the high rate of large rearrangements with different break points, and the presence of complex alleles carrying various mutations. Some less common mutations are highly prevalent in specific populations due to founder effects. These should be considered in the genetic diagnosis of 21OHD when only screening for otherwise common CYP21A2 mutations. CYP21A2 gene duplications should be considered in carriers of the p.Gln318X mutation to provide the correct molecular genetic diagnosis. Molecular genetic diagnosis is essential to provide the correct diagnosis and allows for appropriate clinical and genetic counselling.

Background Distress in patients with diabetes is a condition that has received significant attention in recent years; however, data regarding the psychological assessment and the impact of the emotional burden of diabetes among the Roma population are still scarce in the medical literature. Material and methods We conducted an observational, transversal study that included 310 adult patients with diabetes mellitus, aged between 18 and 85 years old, of which the majority (61%) were women; patients were selected from a tertiary hospital providing diabetes care; diabetes distress was evaluated using a standardized questionnaire, the diabetes distress scale (DDS), validated on Romanian patients. Results In the study population, a great proportion of patients showed diabetes distress, with 24.8% (N=82) having moderate distress and 29.7% (N=121) having severe distress. In the Caucasian group, there were significantly more patients without distress than in the Roma patients,while on the contrary, more Roma patients experienced severe distress compared to the opposite group (64.5%, N=78 versus 35.5%, N=43). In the Caucasian group, a statistical significance was observed regarding interpersonal distress, with Caucasian women having a higher score than men. Concerning the Roma patients, total DDS and all subscales´ scores were statistically significant, with Roma women having higher scores than men. A statistical significance was observed between ethnicity and diabetes distress scores, with the Roma population having higher median values than Caucasian patients. It was also demonstrated that the lack of education, a higher diabetes evolution, and a higher glycated hemoglobin (HbA1c) level (above 8%) have influenced the risk of severe DDS in the Caucasian group, while in the Roma patients, employment status (being unemployed) represents a risk factor for severe DDS. Conclusion The Roma patients included in our study experienced higher distress scores compared to Caucasians. These results are substantial as they emphasize the need to include the evaluation of diabetes distress in clinical practice to facilitate the early initiation of intervention measures. There is nevertheless limited data regarding this particular ethnic group; therefore, further research is still needed.

Congenital adrenal hyperplasia (CAH) is an endocrine autosomal recessive disorder with various symptoms of diverse severity. Mild hyperandrogenemia is the most commonclinical feature in non-classic CAH patients and 95% of the cases are identified by mutations in the CYP21A2 gene. In the present study, the second most common cause for non-classic CAH (NC-CAH), 11β-hydroxylase deficiency due to mutations in the CYP11B1 gene, is investigated. Screening of the CYP21A2 and CYP11B1 genes by direct sequencing was carried out for the detection of possible genetic defects in patients with suspected CAH. It wasobserved that CYP11B1 variants co-exist only in rare cases along with mutations in CYP21A2 in patients clinically diagnosed with CAH. A total of 23 NC-CAH female patients out of 75 were identified with only one mutation in the CYP21A2 gene. The novel CYP11B1 gene mutation, p.Val484Asp, was identified in a patient with CAH in the heterozygous state. The structural characterization of the novel p.Val484Asp was found to likely cause distortion of the surrounding beta sheet and indirect destabilization of the cavity that occurs on the opposite face of the structural elements, leading to partial impairment of the enzymatic activity. CYP21A2 gene mutations are the most frequent genetic defects in cases of NC-CAH even when these patients are in the heterozygous state. These mutations have a diverse phenotype giving rise to a variable extent of cortisol synthesis impairment; it is also clear that CYP11B1 mutants are a rare type of defects causing CAH.

Germline mutations in DNA repair-related genes have been recently reported in cases with familial non-medullary thyroid carcinoma (FNMTC). A Portuguese family from the Roma ethnic group with four members affected with papillary thyroid carcinoma (PTC), and three members with multinodular goiter (MNG) was identified. The aim of this study was to investigate the involvement of DNA repair-related genes in the etiology of FNMTC in this family and in the Roma ethnic group. Ninety-four hereditary cancer predisposition genes were analyzed through next-generation sequencing. Sanger sequencing was used for variant confirmation and screening. Twelve polymorphic markers were genotyped for haplotype analysis in the CHEK2 locus. A germline pathogenic frameshift variant in the CHEK2 gene [c.596dupA, p.(Tyr199Ter)] was detected in homozygosity in the proband (PTC) and in his brother (MNG), being heterozygous in his mother (PTC), two sisters (PTC), and one nephew (MNG). This variant was absent in 100 general population controls. The screening of the CHEK2 variant was extended to other Roma individuals, being detected in 2/33 Roma patients with thyroid cancer, and in 1/15 Roma controls. Haplotype segregation analysis identified a common ancestral core haplotype (Hcac), covering 10 Mb in the CHEK2 locus, shared by affected CHEK2 variant carriers. Analysis of 62 individuals CHEK2 wild-type indicated that none presented the Hcac haplotype. The estimated age for this variant suggested that it was transmitted by a relatively recent common ancestor. We identified a founder CHEK2 pathogenic variant, which is likely to underlie thyroid cancer and other cancer manifestations in the Roma population.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene. The residual enzyme activity is strongly associated with the phenotype. We describe a rare case of CAH with a rare CYP21A2 mutation. The patient was a one-year-old Japanese boy. At 16 days old, he was referred to our hospital because of elevated serum 17-OH-progesterone (17-OHP) levels in neonatal screening. The compound heterozygous mutations (IVS2-13 A/C>G, and p.E431K) in CYP21A2 were identified at 2 months old, and we diagnosed non-classical CAH, since he did not have significant physical signs (pigmentation and salt-wasting). However, his body weight decreased, and his serum 17-OHP level (99.5 ng/mL) was elevated at 3 months old. Steroid replacement therapy was started at 3 months old. Our patient's clinical course resembled simple virilizing (SV) CAH, but classification was difficult because the patient showed increased renin activity indicating an aldosterone deficiency, and late onset of symptoms. While the IVS 2-13 A/C>G mutation is common in the classical form of CAH, p.E431K is a rare point mutation. Functional analysis revealed that the residual enzyme activity of p.E431L was 5.08±2.55% for 17-OHP and 4.12±2.37% for progesterone, which is consistent with SV CAH. p.E431 is localized in the L-helix near the heme-binding site. The mutation might interfere with heme binding, leading to deactivation of CYP21A2. This report showed that CYP21A2 p.E431 has an important effect on enzyme activity.

The aim of this study was to analyze Killer Ig-Like Receptor (KIR) gene polymorphisms in Roma people from Republic of Macedonia. The studied sample consists of 103 healthy unrelated individuals, aged 20-45 years. All individuals are of Roma origin, residents of different geographical regions (Gostivar, Skopje, and Kochani). The population genetics analysis package, Arlequin, was used for analysis of the data. We found that all 16 KIR genes were observed in the Roma individuals and framework genes (KIR3DL3, KIR3DP1, KIR- 2DL4, and KIR3DL2) were present in all individuals. The frequencies of other KIR genes were: KIR2DP1 (1), KIR2DL1 (0.961), KIR2DL2 (0.544), KIR2DL3 (0.874), KIR2DL5 (0.311), KIR3DL1 (0.990), KIR- 2DS1 (0.330), KIR2DS2 (0.553), KIR2DS3 (0.359), KIR2DS4 (0.981), KIR2DS5 (0.291), and KIR3DS1 (0.379). The results of tested linkage disequilibrium (LD) among KIR genes demonstrated that KIR genes present a wide range of linkage disequilibrium. The obtained results for KIR genes and genotype frequencies in Macedonian Roma individuals can be used for anthropological comparisons.

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency is a common inherited disorder of adrenal hormone biosynthesis due to mutations in the 21-hydroxylase gene, CYP21A2. Genotyping for ten of the most frequent mutations was performed in 84 Portuguese CAH patients: 10 salt-wasters, 6 simple-virilizers and 68 non-classical patients. The patients were diagnosed by a level of 17-hydroxyprogesterone above 10 ng/ml either in basal conditions or after an ACTH 0,25 mg IV Test. A variety of genotyping techniques were used to detect these ten mutations. CYP21A2 mutations were detected in 91.7% (77/84) of the patients. The frequency of alleles carrying two or more CYP21A2 mutations (9.5% - 16/168) is higher than in other populations. The most frequent mutations identified in our population were V281L (41.7%) and deletions/conversions involving the promoter region of the CYP21A2 gene (28.3%). A decreased frequency of IVS2-12C/A>G mutation (5.6%) was the most characteristic feature of our population. This study allow the characterization of the mutational spectrum of CAH patients, mainly non-classical CAH, with 21-hydroxylase deficiency from Portugal showing specific genetic features of this population which reveals differences with worldwide countries.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder with impaired function of the adrenal cortex caused by mutations in the CYP21A2 gene. Deficiency of steroid 21-hydroxylase accounts for 80-95% of CAH cases. Testicular adrenal rest tumours (TART) may be prevalent in up to 95% of CAH adults and may already appear during childhood. Whether genotype sub-types can account for the development of TART has not been investigated previously. We therefore investigated this by coupling clinical information of CAH patients with information of their genetic mutation. In 49 male patients (age 2.6-40.3 years) with 21-hydroxylase deficiency, testicular ultrasound examinations were performed and CYP21A2 genotypes determined. These were grouped according to the residual 21-hydroxylase activity: group Null (complete enzyme impairment), group A (almost complete enzyme impairment), group B (severe enzyme impairment) and group C (partial impairment). TART were observed in 27 of 49 patients (55%). For the 23 patients younger than 18 years, TART were present in 11 (48%), the youngest patient being 7.5 years old. The presence of TART was dependent on the CYP21A2 genotype: 27 of 37 patients (73%) with the most severe mutations (groups Null and A) had TART, whereas none of 12 patients with the milder mutations (groups B and C) had TART. We conclude that TART were most frequently detected in patients with severe CYP21A2 mutations, and may occur already in early childhood in such patients.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) is a common autosomal recessive disorder. Our objective was to identify the 21-hydroxylase active gene, CYP21A2 mutations in Malaysian 21-OHD patients using different techniques. Blood samples were obtained from 97 Malaysian 21-OHD patients, which included 40 siblings from 19 families. We used various techniques which include restriction enzyme digestion, Southern blot, multiple ligation-dependent probe amplification (MLPA) and sequencing to elucidate CYP21A2 mutations. Homozygous and compound heterozygous mutations were identified in 95 of the 97 patients (98%). Deletions of CYP21A2 were found in 43 patients (44.3%). Deletions identified in CYP21A2 gene were the usual 30-kb deletion comprising 3'UTR CYP21A1P, C4B and 5'CYP21A2, complete deletion of CYP21A2 gene, deletion in exons 1-3, exons 1-6 and exons 1-8 of CYP21A2. The common mutations identified in CYP21A2 gene were deletion/conversion (22.6%), p.R356W (22%), IVS2-13A/C>G (21.3%), p.I172N (5.3%), p.Q318X (5.3%), and p.P30L (1.03%). This is the first report of the mutation frequency in CYP21A2 gene among the Malay ethnic group. Two novel mutations, c.Y97insT and p.L345P were identified in our patients. Our results show good phenotype-genotype correlation in most of the cases, although clinical variations were identified in some patients. The study has found various mutations including deletions in CYP21A2 gene in Malaysian patients with 21-hydroxylase deficiency using the MLPA technique that is being widely used in present laboratory settings.

Congenital adrenal hyperplasia (CAH) is one of the most common inherited metabolic disorders. It includes a group of autosomal recessive disorders caused by the deficiency of one of the enzymes involed in one of the various steps of adrenal steroid synthesis. The most common form of CAH (95%) is caused by mutations in CYP21A2, the gene encoding the adrenal steroid 21-hydroxylase enzyme (P450c21). Two major phenotype are recognized in 21-OHD: classic and non-classic. Classic CAH is clinically categorized in two groups: the simple-virilising and the salt-wasting form. The National Hospital of Pediatrics (NHP) in Hanoi is an 1100 bed tertiary referral centre servicing approximately 30 million people from northern provinces of Vietnam. At the start of 1999 there were 91 children with CAH due to 21-hydroxylase deficiency (21-OHD) managed at NHP. By June 2012 this increased to 624 [98.2% due to 21-OHD], representing a more than six fold increase over 12 years. Number of new cases ranged from 40 to 70 per year. We aim to determine the mutations in the CYP21A2 gene in Vietnamese patients with CAH and attempt a genotype-phenotype correlation. Molecular analysis was performed using PCR, multiplex ligation-dependent probe amplification and direct sequencing of PCR products of the CYP21A2 gene in 81 CAH patients (39 male and 42 female). Correlation between phenotype and genotype was evaluated based on identified mutations and clinical manifestations. Mutations were identified in 92.6% mutant alleles, 22 genotypes were found in 81 cases. Seven different causative mutations were identified in CYP21A2 including one novel mutation. The most frequent genetic defect in the classic salt-wasting and simple virilizing forms was the IVS2-13A/C>G (54 alleles; 36%) mutation, followed by Large lesion (42 alleles; 28%) including exon 1 deletion (2 alleles), exon 1-3 deletion (10 alleles), exon 1-6 deletion (4 alleles), exon 1-8 deletion (2 alleles) and larger deletion (24 alleles); p.R356W (26 alleles; 17.3%); p.l172N (15 alleles; 10%). The rarer mutations were novel one p.R484fsX541 (6 alleles; 4%); p.Q318X (4 alleles; 2.7%) and p.R426C (3 alleles; 2%). The majority of patients (61 cases; 75.3%) were homozygotes. Four cases were compound heterozygous. Thirteen patients had only a heterozygous mutation detected. Genotype accurately predicted phenotype in 93.8 and 100% of patients with salt-wasting and simple virilizing, respectively. The spectrum of mutations of the CYP21A2 gene in Vietnamese patients is comparable to the some reported in other Asian population. Large deletion accounts for nearly one-third of the genetic defects. Therefore, laboratory should include methods for detecting point mutations as well as large deletions. Genotype-Phenotype correlation was high in the studied patients.