Comprehensive study of chromosomal CNVs and genomic variations predicting overall survival in Myelodysplastic syndromes.

INTRODUCTION: Myelodysplastic syndrome (MDS) is a heterogeneous disease characterized by cytopenia, marrow dysplasia and has a propensity to develop into acute myeloid leukemia (AML). The disease progression is majorly affected by genetic defects. However, about 40% - 50% of patients with MDS present with a normal karyotype and develop different courses of disease. Hence there remains a room to advance the biological understanding and to find molecular prognostic markers for cytogenetically normal (CN) MDS. METHODS: We performed a high-resolution CGH + SNP array along with NGS of 77 primary diagnosed MDS patients and also they were clinically followed up. RESULTS: Our study revealed 82 clinically significant genomic lesions (losses/gains) in 49% of MDS patients. CGH + SNP array reduced the proportion of normal karyotype by 30%. SNP array in combination with NGS confirmed the biallelic loss of function of the TP53 gene (2/6), which is a clinically relevant biomarker and new genetic-based MDS entity i.e. MDS-biTP53 as per the new WHO classification 2022. Genomic region 2p22.3 presented with frequent lesions and also with a more hazard ratio (2.7, 95% CI 0.37 - 21) when analyzed by Kaplan Meier survival analysis. CONCLUSION: CGH + SNP array changed the cytogenetic and IPSS-R risk group in 18% and 13% of patients respectively with an improved prediction of prognosis. This study emphasizes the cytogenetic heterogeneity of MDS and highlights that abnormality with chromosome 2 may have a diagnostic and prognostic impact.

Frequency and pattern of chromosomal abnormalities in acute myeloid leukemia from Western India: A retrospective study.

Context: Chromosomal abnormalities play an important role in diagnosis and prognosis of hematological diseases. Aims: The aim of the present study was to study the pattern and frequency of chromosomal aberrations in acute myeloid leukemia (AML) subgroups from western India. Settings and Design: A retrospective study was conducted through evaluating laboratory proforma which were filled during 2005 to 2014 for diagnosis and treatment of AML subjects. Methods and Material: We have studied chromosomal aberrations in 282 subjects with AML from western India. AML patients were sub-grouped according to FAB classification. Cytogenetic study using conventional cytogenetics (GTG-banding) and Fluorescence in situ hybridization (FISH) was carried out using FISH probes (AML1/ETO, PML/RARA, CBFB). Statistical analysis: Student's t test for continuous variables and Pearson's Chi-squared test for categorical variables were used to identify the relationship between variables. Results: Cytomorphological study revealed AML- M3 as most frequent (32.3%) group followed by AML-M2 (25.2%) and AML-M4 (19.9%). Chromosomal abnormalities were identified in 145 (51.42%) of the total AML cases. A high frequency (38.6%) of chromosomal abnormalities was identified in AML-M3 subgroup as compared to AML-M2 (31%) and AML-M4 (20.6%). Conclusions: Cytogenetic study is important for the diagnosis and management of the AML patients. Our study identified chromosomal abnormalities in AML subgroups with varied frequencies. It is important in diagnosis and monitoring of the disease. As younger AML patients were more affected in our study, etiological factors such as environmental factors need to be studied. Combination of conventional cytogenetics and FISH has an advantage of identifying high frequency of chromosomal aberrations in AML patients.

Synergetic effect of Azacitidine and Sorafenib in treatment of a case of myeloid neoplasm with sole chromosomal abnormality t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement.

The sole t(8;22)(p11.2;q11.2)/BCR- FGFR1 chromosomal abnormality formerly known as aCML is an extremely rare disease entity with a history of rapid progression. Though patients resemble phenotypically chronic myeloid leukemia, the treatment of patients with sole BCR-FGFR1 rearrangement are still challenging for clinicians due to rapid progressive nature and unavailability of uniform treatment guidelines. In present case study, we describe a case of myeloid neoplasm with sole chromosomal abnormality of t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement which is successfully managed by Sorafenib with Azacitidine. Hence our case report suggests that combination of Sorafenib and Azacitidine treatment is effective in sole BCR-FGFR1 rearrangement, however this combination therapy should be studied in large clinical trials.

Comprehensive molecular analysis identifies eight novel variants in XY females with disorders of sex development.

Disorders of sex development (DSD) are a group of clinical conditions with variable presentation and genetic background. Females with or without development of secondary sexual characters and presenting with primary amenorrhea (PA) and a 46,XY karyotype are one of the classified groups in DSD. In this study, we aimed to determine the genetic mutations in 25 females with PA and a 46,XY karyotype to show correlations with their phenotypes. Routine Sanger sequencing with candidate genes like SRY, AR, SRD5A2, and SF1, which are mainly responsible for 46,XY DSD in adolescent females, was performed. In a cohort of 25 patients of PA with 46,XY DSD, where routine Sanger sequencing failed to detect the mutations, next-generation sequencing of a targeted gene panel with 81 genes was used for the molecular diagnosis. The targeted sequencing identified a total of 21 mutations including 8 novel variants in 20 out of 25 patients with DSD. The most frequently identified mutations in our series were in AR (36%), followed by SRD5A2 (20%), SF1 (12%), DHX37 (4%), HSD17B3 (4%), and DMRT2 (4%). We could not find any mutation in the DSD-related genes in five (20%) patients due to complex molecular mechanisms in 46,XY DSD, highlighting the possibility of new DSD genes which are yet to be discovered in these disorders. In conclusion, genetic testing, including cytogenetics and molecular genetics, is important for the diagnosis and management of 46,XY DSD cases.

Comprehensive analysis of genetic factors predicting overall survival in Myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a group of clonal hematological disease with high risk of progression to AML. Accurate risk stratification is of importance for the proper management of MDS. Genetic lesions (Cytogenetic and Molecular mutations) are known to help in prognosticating the MDS patients. We have studied 152 MDS patients using cytogenetics and next generation sequencing (NGS). These patients were evaluated and as per cytogenetic prognostic group, majority (92.1%) of the patients classified as good (81.6%) and intermediate (10.5%) group. The NGS identified 38 different gene mutations in our cohort. Among 111 MDS patients with mutations, the most frequent mutated genes were SF3B1 (25.2%), SRSF2 (19%) U2AF1 (14.4%) ASXL1 (9.9%) RUNX1 (9.9%) TET2 (9%), TP53 (9%), ATM (6.3%), NRAS (5.4%) and JAK2/3 (5.4%). The survival analysis revealed that the mutations in TP53, JAK2/3, KRAS, NRAS and ASXL1 were significantly (P < 0.05) associated with poor survival of the patients. The univariate cox and multivariate cox analysis of our study suggested that the age, marrow morphology, cytogenetic and gene mutations with IPSS-R should be considered for prognosticating the MDS patients. We have proposed M-IPSS-R which changed the risk stratification i.e. 66.3% patients had decreased risk whereas 33.75% showed increased risk compared to IPSS-R. The survival analysis also showed that the M-IPSS-R were more significant in separating the patients as per their risk than the IPSS-R alone. The change in risk stratification could help in proper strategy for the treatment planning.

Novel deletion of exon 3 in TYR gene causing Oculocutaneous albinism 1B in an Indian family along with intellectual disability associated with chromosomal copy number variations.

BACKGROUND: Oculocutaneous albinism (OCA) is an autosomal recessive disorder characterized by hypo-pigmentation of skin, hair, and eyes. The OCA clinical presentation is due to a deficiency of melanin biosynthesis. Intellectual disability (ID) in OCA cases is a rare clinical presentation and appropriate diagnosis of ID is challenging through clinical examination. We report an Indian family with a rare co-inheritance of OCA1B and ID due to a novel TYR gene variant and chromosomal copy number variations. METHODS: We have done a study on three siblings (2 males and 1 female) of a family where all of them presented with hypopigmented skin, hair and eyes. The male children and their father was affected with ID. Targeted exome sequencing and multiplex ligation-dependent probe amplification analysis were carried out to identify the OCA1B and ID associated genomic changes. Further Array-CGH was performed using SurePrint G3 Human CGH + SNP, 8*60 K array. RESULTS: A rare homozygous deletion of exon 3 in TYR gene causing OCA1B was identified in all three children. The parents were found to be heterozygous carriers. The Array-CGH analysis revealed paternally inherited heterozygous deletion(1.9 MB) of 15q11.1-> 15q11.2 region in all three children. Additionally, paternally inherited heterozygous deletion(2.6 MB)of 10q23.2-> 10q23.31 region was identified in the first male child; this may be associated with ID as the father and the child both presented with ID. While the 2nd male child had a denovo duplication of 13q31.1-> 13q31.3 chromosomal region. CONCLUSION: A rare homozygous TYR gene exon 3 deletion in the present study is the cause of OCA1B in all three children, and the additional copy number variations are associated with the ID. The study highlights the importance of combinational genetic approaches for diagnosing two different co-inherited disorders (OCA and ID). Hence, OCA cases with additional clinical presentation need to be studied in-depth forthe appropriate management of the disease.

Nitric oxide synthase-2 (NOS2) gene polymorphism c.1832C>T (Ser608Leu) associated with nitrosative stress in Fanconi anaemia.

Fanconi anemia (FA) occurs due to genomic instability with predisposition to bone marrow failure, phenotypic abnormalities and cancers. Though mutations in 22 genes leading to DNA repair defect have been identified, the cellular factor such as oxidative stress has also shown to be associated with FA. Nitrosative Stress (NS) is biochemically correlated to many oxidative stress related disorders and the NS as a pathological hallmark in FA has been so far overlooked. We carried out the study first time in Indian patients with FA with an objective to understand the role of NS in the pathogenesis of FA. The study was carried out in 70 FA subjects. The FA subjects were diagnosed by chromosomal breakage analysis. Molecular study was carried out by Next Generation Sequencing and Sanger sequencing. The 3-nitrotyrosine [3-NT] levels were estimated through enzyme-linked immuno-sorbent assay (ELISA) and the nitric oxide synthase genes- NOS1 (c.-420-34221G>A (rs1879417), c.-420-10205C>T (rs499776), c.4286+720G>C (rs81631)) and NOS2 (c.1823C>T (p. Ser608Leu) (rs2297518)) polymorphism were studied by direct sequencing. Chromosomal breakage analysis revealed a high frequency of chromosomal breaks (Mean chromosomal breakage-4.13 ± 1.5 breaks/metaphase) in 70 FA patients as compared to the control. Molecular studies revealed FANCA (58.34%), FANCG (18.34%) and FANCL (16.6%) complementation groups. The 3-nitrotyrosine [3-NT] levels showed to be significantly (p < 0.05) elevated in FA subjects when compared to the age match controls. Genotyping of the NOS2 gene c.1823C>T (p. Ser608Leu) (rs2297518), showed statistically significant (P < 0.05) association with FA. Elevated level of 3-NT is one of the cause of NS and NOS2 gene polymorphism associated with FA is an important target in the treatment regimen.

Severe telomere shortening in Fanconi anemia complementation group L.

Fanconi Anemia (FA) is a rare genetic disease with the incidence of 1 in 360,000 and is characterised by bone marrow failure, physical abnormalities, pancytopenia, and high frequency of chromosomal breakage and increased risk of evolving into malignancy. Telomere plays an important role in genomic stability, ageing process and cancers. Telomere shortening has been reported in FA. We studied telomere length in FA subjects and compared with complementation groups. Chromosomal breakage analysis from PHA stimulated, MMC induced peripheral blood culture was carried out in 37 clinically diagnosed FA. Molecular study of FANCA, G, and L was done through Sanger sequencing and next generation sequencing. Telomere length was estimated using real time quantitative polymerase chain reaction (qPCR) method. Student t-test was applied to test the significance. A high frequency of chromosomal breakage was observed in all the patients compared to healthy controls. We found significantly shorter telomere length in all the three complementation groups compare to age matched healthy controls. Among all complementation groups, FANCL showed severe telomere shortening (P value 0.0001). A negative correlation was observed between telomere length and chromosomal breakage frequency (R = -0.3116). Telomere shortening is not uncommon in FA subjects. However the telomere length shortening is different in complementation groups as FANCL showed severe telomere shortening in FA subjects. Though BM transplantation is essential for the management of the FA subjects, the telomere length can be considered as biological marker to understand the prognosis of the disease as FA subjects primarily treated with androgens.

array-CGH revealed gain of Yp11.2 in 49,XXXXY and gain of Xp22.33 in 48,XXYY karyotypes of two rare klinefelter variants.

Klinefelter syndrome (KS) variants often share common features with classical syndrome but some of these variants present with a distinct phenotype. The incidence of sex chromosome tetrasomy and pentasomy are very less and generally diagnosed after prepubertal age. The early diagnosis of complex and unclassified syndromes and it's correlation with genotype is necessary for personalized treatment as well as genetic counselling of the affected families. We describe clinical presentation, and genetic diagnosis of two cases of variant KS. Our first case, a 4 year old male child presented with generalized tonic-clonic seizures (GTCSs), delayed milestones and dysmorphic features while case 2, a-21 years old male who had history of seizures and delayed puberty came to our lab for genetic diagnosis. The chromosomal analysis of case 1 and 2 showed 49,XXXXY and 48,XXYY karyotype respectively. The karyotype results were confirmed with fluorescence in situ hybridization (FISH) and array-CGH analysis. The FISH results were found to be consistent with karyotype but the array-CGH results showed the extra gain of region Yp11.2 in case 1 while the extra gain of region Xp22.33 in case 2. The cases were confirmed as variant KS on the basis of additional sex chromosomes and clinical presentation of deteriorated brain development. The present study suggests that the high doses of sex chromosome linked genes including pseudoautosomal region (PAR) caused the abnormal brain development. The combination of molecular techniques should be utilized for the diagnosis of such complex cases to understand the genotype-phenotype correlation and appropriate genetic counseling.

Chromosomal Aberrations in Primary Amenorrhea: A Retrospective Study.

OBJECTIVES: The aim of this study was to estimate the frequency of chromosomal abnormalities and establish the association with clinical of factors such as secondary sexual characters and gonad development in primary amenorrhea (PA). STUDY DESIGN: The study was carried out in a large cohort of PA. The chromosomal aberrations were correlated with secondary sexual characters and anatomical abnormalities. MATERIALS AND METHODS: The data of 490 cases of PA were collected retrospectively. The chromosomal preparations were done from the peripheral blood and subjected to giemsa-trypsin-giemsa banding and karyotyped according to the International System of Human Cytogenetic Nomenclature 2013. The fluorescence in situ hybridization was carried out using centromeric and whole painting probes for X and Y chromosome. STATISTICAL ANALYSIS: Statistical analysis of the data was performed using online version of social science statistics software. RESULTS: A high frequency of abnormal uterus (81.9%) and ovaries (86.7%) were detected in our study. A total of 121 (24.7%) cases were identified with abnormal karyotype. The numerical chromosomal abnormalities were identified in 53 (43.8%) cases while structural abnormalities were identified in 32 (26.4%) cases. The XY karyotype was detected in 29.8% females with PA. The PA individuals with anatomical abnormalities (84.3%) had a high frequency (24.6%) of chromosomal aberrations. CONCLUSIONS: The present study concluded that cytogenetics plays an important role in precise diagnosis which helps in the management of PA. The cytogenetic analysis should be carried out to know the genetic basis of PA.

Lack of association between functional polymorphism of DNA repair genes (XRCC1, XPD) and clinical response in Indian chronic myeloid leukemia patients.

The resistance for the tyrosine kinase inhibitors in chronic myeloid leukemia (CML) occurs mainly due to BCR/ABL1 dependent and independent mechanisms. The defective DNA repair due to functional polymorphisms in DNA repair genes, might act as an etiological factor for leukemia progression. The study was carried out to understand the role of DNA repair genes (XRCC1, XPD) polymorphisms in Imatinib mesylate (IM) resistant CML patients. The study was carried out in total 87 CML patients (43 nonresponders-cases and 44 responders) who were treated with Imatinib. The treatment and follow-up was done according to European LeukemiaNet guidelines. The genotyping of selected SNPs were studied using RFLP and confirmed with Sanger sequencing (20%). The statistical analysis was performed using online tools (Socscistatistics and GraphPad InStat software). In our study no significant association was inferred between genotypes of DNA repair genes (XRCC1; rs1799782, rs25487, and XPD; rs13181) and complete cytogenetic response as well as molecular response. However there might be a possibility of association between XRCC1 Arg399Gln genotype AA/GA and cytogenetic response though it is statistically insignificant (p > 0.05). Though none of the genotypes of the DNA repair genes showed association with IM response, near association between XRCC1Arg399Gln genotype and cytogenetic response observed in our study. Hence, large sample size should be studied to establish the association of SNPs of DNA repair genes and IM response. Our study is a novel and important to explain the role of DNA repair genes polymorphisms in IM resistance.

Partial trisomy 9 (9pter->9q22.1) and partial monosomy 14 (14pter- >14q11.2) due to paternal translocation t(9;14)(q22.1;q11.2) in a case of Dysmorphic features.

Trisomy 9 including mosaic and partial trisomy is less frequently seen chromosomal abnormality in live born children. The pure or partial trisomy 9 frequently been reported in prenatal diagnosis and product of conception. However few studies reported partial trisomy 9 in live born children. In addition data on genotype and phenotype correlation of partial trisomy is not well understood except few case reports. Here we report a case of partial trisomy 9 and monosomy 14 with a 46,XY,der(9)t(9;14)(q22.1;q11.2)pat,-14 karyotype in a 5-year old dysmorphic child. The proband was confirmed as trisomic for 9pter->9q22.1 and monosomic for 14pter->q11.2 due to paternal t(9;14)(q22.1;q11.2) balanced translocation using a combination of conventional and molecular cytogenetic (fluorescence in situ hybridization, array-comparative genomic hybridization) techniques. The clinical features similar to pure trisomy 9 is due to duplication of the large region of chromosome 9. However, the present report of partial trisomy 9 and monosomy 14 is a novel case report and showing comparatively longer survival which have not been previously reported in the literature. The parent of the proband was counseled for the future pregnancies.