Krüppel-like factor 1 (KLF1) gene single nucleotide polymorphisms in sickle cell disease and its association with disease-related morbidities.

Sickle cell disease has varied clinical symptoms, and patients having high fetal hemoglobin (HbF) have milder symptoms. Various genetic factors are known to modulate the HbF levels. Krüppel-like factor 1 (KLF1) is a transcription factor that regulates the beta-like globin gene expression. Any variation in KLF1 gene may alter the sickle cell disease phenotype. Xmn-I polymorphism is also known to regulate the gamma globin gene expression. Present studies were carried out to investigate the effect of KLF1 gene mutations and Xmn-I polymorphism on the sickle cell disease severity and to ascertain the genotype-phenotype correlation. One hundred and eighteen sickle cell disease patients having a median follow-up of 5 years (3-10 years) were recruited. Clinical details were recorded from their retrospective medical records. Xmn-I polymorphism were analyzed using PCR-RFLP method. Variations in KLF1 gene were identified using Sanger sequencing. Out of 118 patients, 24 had acute chest syndrome and 21 patients had more than 2 pain episodes per year. There were no significant differences in sickle cell disease-related morbidities in male and females barring leg ulcers. A total of 6 polymorphism were observed in KLF1 gene, out of which 3 are novel (c.-304G > C, c.*141A > G and c.*178A > G). No statistically significant association of any of SNPs identified in KLF1 gene or Xmn-I polymorphism was seen with HbF levels as well as the sickle cell disease-related morbidities. No association exists between fetal hemoglobin or sickle cell disease-related morbidities and Xmn-I polymorphism or with SNPs identified in KLF1 gene in the studied cohort.

Prevalence and spectrum of mutations causing G6PD deficiency in Indian populations.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human erythroenzymopathy affecting around 10% of the world population. India is endemic for malaria and antimalarial drugs are known to induce haemolysis in G6PD deficient individuals. Here we report the prevalence as well as the molecular diversity of G6PD deficiency in geographical regions of India. METHODS AND RESULTS: A total of 20,896 individuals (11,838 males and 9058 females) were screened by DPIP dye decolorisation method followed by quantitation of G6PD enzyme activity on the suspected samples. Molecular analysis was undertaken in a total of 350 G6PD deficient individuals by PCR-RFLP and DNA sequencing. A structural characteristic of the novel variant was deduced by using DynaMut web-server. The prevalence rate of G6PD deficiency varied between 0.8 and 6.3% with an overall prevalence of 1.9%. A total of twelve mutations were identified. Of the total deleterious alleles detected G6PD Orissa (56.5%) was found to be the most predominant variant followed by G6PD Mediterranean (23.6%). G6PD Mediterranean, G6PD Kaiping and G6PD Mahidol were found to be severely deficient variant and 14.1% of them showed undetectable activity. A novel mutation c.544C➔G (R182G) in exon 6 was identified in one tribal male where substitution of arginine by glycine, likely causes the alteration in the alpha helix leading to disruption of secondary structure of the protein. CONCLUSION: There are large differences in the distribution of G6PD causal variants between Indian states, and this may have implications for the treatment in the malaria endemic areas.