Background: Congenital dyserythropoietic anemias (CDAs) are a very rare and heterogeneous group o... more Background: Congenital dyserythropoietic anemias (CDAs) are a very rare and heterogeneous group of disorders characterized by ineffective erythropoiesis. CDA II is caused by mutations in the SEC23B gene. The most common mutation reported in India is c.1385A>G, p.Y462C. There is no simple and cost-effective confirmatory diagnostic test available for CDA, and therefore, many patients remain undiagnosed. High-resolution melting (HRM) analysis is a polymerase chain reaction (PCR) based technique applied to identify genetic differences and scan nucleic acid sequences. HRM can be used to rapidly screen the common mutation causing CDA II in the Indian population. Objective: To study the use of High-Resolution Melting Curve Analysis to detect common mutation causing CDA II in the Indian population.Method:10 Indian families havingSEC23B (Y462C) mutation causing CDA II are considered for this study. HRM was used to check the presence of Y462C mutation. To verify the reliability of the HRM ...
Hexokinase (EC 2.7.1.1, Adenosine Tri Phosphate (ATP): D-hexose-6-phosphotransferase) is a crucia... more Hexokinase (EC 2.7.1.1, Adenosine Tri Phosphate (ATP): D-hexose-6-phosphotransferase) is a crucial regulatory enzyme of the glycolytic pathway (Embden-Meyerhof pathway). Hexokinase deficiency is associated with chronic non-spherocytic haemolytic anaemia (HA) with some exceptional cases showing psychomotor/mental retardation and fetus death. The proband is a four-and-half-year-old female child born of a four-degree consanguineous marriage hailing from South India with autosomal recessive congenital HA associated with developmental delay. She was well till 3 months of her age post an episode of diarrhoea when she was noted to be severely anaemic and requiring regular transfusions. The common causes of HA, haemoglobinopathies, red cell membranopathies and common red cell enzymopathies (G6PD, GPI, PK and P5N) were ruled out. Targeted analysis of whole exome sequencing (WES) using an insilico gene panel for hereditary anaemia was performed to identify pathogenic variants in the patient. ...
To provide prenatal diagnosis of pyruvate kinase deficiency by direct DNA analysis in an Indian f... more To provide prenatal diagnosis of pyruvate kinase deficiency by direct DNA analysis in an Indian family. This case report describes diagnosis of a novel homozygous mutation in PKLR gene that subsequently helped the family in the next pregnancy. Advancement in molecular genetics has resulted in the prenatal diagnosis of relatively uncommon genetic disorders like pyruvate kinase deficiency. This case reiterates the importance of application of molecular genetics in clinical practice and prenatal diagnosis especially for rare, incurable genetic disorders.
The group of unstable hemoglobins are associated with congenital non-spherocytic hemolytic anemia... more The group of unstable hemoglobins are associated with congenital non-spherocytic hemolytic anemia due to instability of the hemoglobin molecule. They often lead to formation of the characteristic inclusion bodies or Heinz bodies. To identity the cause of mild anemia, reticulocytosis, and hepatosplenomegly in a case of non-spherocytic hemolytic anemia. A 34-year-old female patient originating from Maharashtra, western India presented with mild anemia and jaundice which had persisted since childhood. Investigations included a complete blood count, screening for red cell membrane protein defects, Hb analysis by high-performance liquid chromatography (HPLC) and cellulose acetate electrophoresis (pH 8.9), heat instability test and DNA sequencing. Hemoglobin analysis by HPLC showed an abnormal peak in the Hb C window (9.8%) with a retention time of 4.90 minutes. Cellulose acetate electrophoresis (pH 8.9) showed a slow moving band (6.15%) between Hb A2 and Hb S. The heat instability test was positive. DNA analysis of α globin genes showed absence of both deletional and non- deletional α thalassemia. DNA sequencing of the β globin gene revealed heterozygosity for a mutation at codon 98 [GTG → ATG, Val → Met], which gives rise to Hb-Koln. Hb Koln is the commonest unstable Hb variant reported from many populations in the world. However, this is the first report of this unstable Hb variant from India.
Eighteen unrelated pyruvate kinase (PK)-deficient Indian patients were identified in the past 4 y... more Eighteen unrelated pyruvate kinase (PK)-deficient Indian patients were identified in the past 4 years with varied clinical phenotypes ranging from a mild chronic haemolytic anaemia to a severe transfusion-dependent disorder. We identified 17 different mutations in the PKLR gene among the 36 mutated alleles. Ten novel mutations were identified: 427G>A, 499C>A, 1072G>A, 1180G>T, 1216G>A, 1220A>G, 644delG, IVS5 (+20) C>A, IVS9 (+44) C>T, and IVS9 (+93) A>C. A severe syndrome was commonly associated with some mutations, 992A>G, 1436G>A, 1220A>G, 644delG and IVS9 (+93) A>C, in the PKLR gene. Molecular graphics analysis of human red blood cell PK (RPK), based on the crystal structure of human PK, shows that mutations located near the substrate or fructose 1,6-diphosphate binding site may change the conformation of the active site, resulting in very low PK activity and severe clinical symptoms. The mutations target distinct regions of RPK structure, including domain interfaces and catalytic and allosteric sites. In particular, the 1216G>A and 1219G>A mutations significantly affect the interdomain interaction because they are located near the catalytic site in the A/B interface domains. The most frequent mutations in the Indian population appear to be 1436G>A (19.44%), followed by 1456C>T (16.66%) and 992A>G (16.66%). This is the first study to correlate the clinical profile with the molecular defects causing PK deficiency from India where 10 novel mutations that produce non-spherocytic haemolytic anaemia were identified.
We report the clinical features and molecular characterization of 23 patients with cyanosis due t... more We report the clinical features and molecular characterization of 23 patients with cyanosis due to NADH-cytochrome b5 reductase (NADH-CYB5R) deficiency from India. The patients with type I recessive congenital methemoglobinemia (RCM) presented with mild to severe cyanosis only whereas patients with type II RCM had cyanosis associated with severe neurological impairment. Thirteen mutations were identified which included 11 missense mutations causing single amino acid changes (p.Arg49Trp, p.Arg58Gln, p.Pro145Ser, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, p.Ala179Thr, p.Thr238Met, and p.Val253Met), one stop codon mutation (p.Trp236X) and one splice-site mutation (p.Gly76Ser). Seven of these mutations (p.Arg50Trp, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, and p.Thr238Met) were novel. Two mutations (p.Gly76Ser and p.Trp236X) were identified for the first time in the homozygous state globally causing type II RCM. We used the three-dimensional (3D) structure of human erythrocyte NADH-CYB5R to evaluate the protein structural context of the affected residues. Our data provides a rationale for the observed enzyme deficiency and contributes to a better understanding of the genotype-phenotype correlation in NADH-CYB5R deficiency.
1. Clin Chim Acta. 2004 Jun;344(1-2):221-4. Hereditary spherocytosis in association with severe G... more 1. Clin Chim Acta. 2004 Jun;344(1-2):221-4. Hereditary spherocytosis in association with severe G6PD deficiency: report of an unusual case. Kedar PS, Colah RB, Ghosh K, Mohanty D. PMID: 15149895 [PubMed - indexed for MEDLINE]. Publication Types: Case Reports; Letter. ...
Background: Congenital dyserythropoietic anemias (CDAs) are a very rare and heterogeneous group o... more Background: Congenital dyserythropoietic anemias (CDAs) are a very rare and heterogeneous group of disorders characterized by ineffective erythropoiesis. CDA II is caused by mutations in the SEC23B gene. The most common mutation reported in India is c.1385A>G, p.Y462C. There is no simple and cost-effective confirmatory diagnostic test available for CDA, and therefore, many patients remain undiagnosed. High-resolution melting (HRM) analysis is a polymerase chain reaction (PCR) based technique applied to identify genetic differences and scan nucleic acid sequences. HRM can be used to rapidly screen the common mutation causing CDA II in the Indian population. Objective: To study the use of High-Resolution Melting Curve Analysis to detect common mutation causing CDA II in the Indian population.Method:10 Indian families havingSEC23B (Y462C) mutation causing CDA II are considered for this study. HRM was used to check the presence of Y462C mutation. To verify the reliability of the HRM ...
Hexokinase (EC 2.7.1.1, Adenosine Tri Phosphate (ATP): D-hexose-6-phosphotransferase) is a crucia... more Hexokinase (EC 2.7.1.1, Adenosine Tri Phosphate (ATP): D-hexose-6-phosphotransferase) is a crucial regulatory enzyme of the glycolytic pathway (Embden-Meyerhof pathway). Hexokinase deficiency is associated with chronic non-spherocytic haemolytic anaemia (HA) with some exceptional cases showing psychomotor/mental retardation and fetus death. The proband is a four-and-half-year-old female child born of a four-degree consanguineous marriage hailing from South India with autosomal recessive congenital HA associated with developmental delay. She was well till 3 months of her age post an episode of diarrhoea when she was noted to be severely anaemic and requiring regular transfusions. The common causes of HA, haemoglobinopathies, red cell membranopathies and common red cell enzymopathies (G6PD, GPI, PK and P5N) were ruled out. Targeted analysis of whole exome sequencing (WES) using an insilico gene panel for hereditary anaemia was performed to identify pathogenic variants in the patient. ...
To provide prenatal diagnosis of pyruvate kinase deficiency by direct DNA analysis in an Indian f... more To provide prenatal diagnosis of pyruvate kinase deficiency by direct DNA analysis in an Indian family. This case report describes diagnosis of a novel homozygous mutation in PKLR gene that subsequently helped the family in the next pregnancy. Advancement in molecular genetics has resulted in the prenatal diagnosis of relatively uncommon genetic disorders like pyruvate kinase deficiency. This case reiterates the importance of application of molecular genetics in clinical practice and prenatal diagnosis especially for rare, incurable genetic disorders.
The group of unstable hemoglobins are associated with congenital non-spherocytic hemolytic anemia... more The group of unstable hemoglobins are associated with congenital non-spherocytic hemolytic anemia due to instability of the hemoglobin molecule. They often lead to formation of the characteristic inclusion bodies or Heinz bodies. To identity the cause of mild anemia, reticulocytosis, and hepatosplenomegly in a case of non-spherocytic hemolytic anemia. A 34-year-old female patient originating from Maharashtra, western India presented with mild anemia and jaundice which had persisted since childhood. Investigations included a complete blood count, screening for red cell membrane protein defects, Hb analysis by high-performance liquid chromatography (HPLC) and cellulose acetate electrophoresis (pH 8.9), heat instability test and DNA sequencing. Hemoglobin analysis by HPLC showed an abnormal peak in the Hb C window (9.8%) with a retention time of 4.90 minutes. Cellulose acetate electrophoresis (pH 8.9) showed a slow moving band (6.15%) between Hb A2 and Hb S. The heat instability test was positive. DNA analysis of α globin genes showed absence of both deletional and non- deletional α thalassemia. DNA sequencing of the β globin gene revealed heterozygosity for a mutation at codon 98 [GTG → ATG, Val → Met], which gives rise to Hb-Koln. Hb Koln is the commonest unstable Hb variant reported from many populations in the world. However, this is the first report of this unstable Hb variant from India.
Eighteen unrelated pyruvate kinase (PK)-deficient Indian patients were identified in the past 4 y... more Eighteen unrelated pyruvate kinase (PK)-deficient Indian patients were identified in the past 4 years with varied clinical phenotypes ranging from a mild chronic haemolytic anaemia to a severe transfusion-dependent disorder. We identified 17 different mutations in the PKLR gene among the 36 mutated alleles. Ten novel mutations were identified: 427G>A, 499C>A, 1072G>A, 1180G>T, 1216G>A, 1220A>G, 644delG, IVS5 (+20) C>A, IVS9 (+44) C>T, and IVS9 (+93) A>C. A severe syndrome was commonly associated with some mutations, 992A>G, 1436G>A, 1220A>G, 644delG and IVS9 (+93) A>C, in the PKLR gene. Molecular graphics analysis of human red blood cell PK (RPK), based on the crystal structure of human PK, shows that mutations located near the substrate or fructose 1,6-diphosphate binding site may change the conformation of the active site, resulting in very low PK activity and severe clinical symptoms. The mutations target distinct regions of RPK structure, including domain interfaces and catalytic and allosteric sites. In particular, the 1216G>A and 1219G>A mutations significantly affect the interdomain interaction because they are located near the catalytic site in the A/B interface domains. The most frequent mutations in the Indian population appear to be 1436G>A (19.44%), followed by 1456C>T (16.66%) and 992A>G (16.66%). This is the first study to correlate the clinical profile with the molecular defects causing PK deficiency from India where 10 novel mutations that produce non-spherocytic haemolytic anaemia were identified.
We report the clinical features and molecular characterization of 23 patients with cyanosis due t... more We report the clinical features and molecular characterization of 23 patients with cyanosis due to NADH-cytochrome b5 reductase (NADH-CYB5R) deficiency from India. The patients with type I recessive congenital methemoglobinemia (RCM) presented with mild to severe cyanosis only whereas patients with type II RCM had cyanosis associated with severe neurological impairment. Thirteen mutations were identified which included 11 missense mutations causing single amino acid changes (p.Arg49Trp, p.Arg58Gln, p.Pro145Ser, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, p.Ala179Thr, p.Thr238Met, and p.Val253Met), one stop codon mutation (p.Trp236X) and one splice-site mutation (p.Gly76Ser). Seven of these mutations (p.Arg50Trp, p.Gly155Glu, p.Arg160Pro, p.Met177Ile, p.Met177Val, p.Ile178Thr, and p.Thr238Met) were novel. Two mutations (p.Gly76Ser and p.Trp236X) were identified for the first time in the homozygous state globally causing type II RCM. We used the three-dimensional (3D) structure of human erythrocyte NADH-CYB5R to evaluate the protein structural context of the affected residues. Our data provides a rationale for the observed enzyme deficiency and contributes to a better understanding of the genotype-phenotype correlation in NADH-CYB5R deficiency.
1. Clin Chim Acta. 2004 Jun;344(1-2):221-4. Hereditary spherocytosis in association with severe G... more 1. Clin Chim Acta. 2004 Jun;344(1-2):221-4. Hereditary spherocytosis in association with severe G6PD deficiency: report of an unusual case. Kedar PS, Colah RB, Ghosh K, Mohanty D. PMID: 15149895 [PubMed - indexed for MEDLINE]. Publication Types: Case Reports; Letter. ...
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