Diagnosis of cystic fibrosis: Indian perspective

Glucose intolerance in children with cystic fibrosis: a developing country's perspective

Background Cystic fibrosis-related diabetes (CFRD) is a common comorbidity reported in patients with cystic fibrosis (CF). There is a dearth of data on glucose intolerance or CFRD in children with CF from developing countries. So, we planned to study the prevalence of abnormal glucose tolerance (AGT) in children with CF and its relation with the duration and severity of CF. Methods We performed an oral glucose tolerance test (OGTT) on children (2-18 years old) having CF for at least 6 months. Two-hour plasma glucose levels on OGTT were correlated with various disease-related factors. Results Out of the 25 children enrolled, there were 18 boys and seven girls. The mean age and duration of CF were 7.9±4.3 and 3.16±2.5 years, respectively. AGT was observed in 16 (64%) children with CF including three (12%) children with CFRD. Children with a duration of CF of 3 years had significantly higher prevalence (81.8%) of AGT when compared with duration ≤3 years (p-value<0.05). Twelve out of 17 (70.6%) children were colonized with Pseudomonas and 12 out of 15 (80%) children >6 years of age had AGT. There was a positive correlation of 2-h glucose value on OGTT with duration of CF and number of hospitalizations with acute pulmonary exacerbations. Conclusions The majority of children having CF for >3 years and/or age >6 years developed AGT. In our clinical setting, an annual screening with OGTT to detect AGT may be required at an early age and duration of CF.

Characterisation of mutations and genotype-phenotype correlation in cystic fibrosis: experience from India

BACKGROUND

Very little is known about the genetics of cystic fibrosis (CF) from the Indian subcontinent. The aims of the study were to identify the mutations and study the relation of genotype with phenotype in Indian children with CF.

METHODS

A total of 100 patients with CF were screened for mutations in the CFTR gene. These included c.1521_1523delCTT (p.F508del) and c.3849+10 kb C>T mutations followed by single strand conformation polymorphism/heteroduplex analysis for mutations in 19 out of 27 exons of the CFTR gene.

RESULTS

At least one mutation was identified in 40 patients. The most common mutation identified was p.F508del; 20 patients were homozygous and 13 heterozygous. In addition, c.3849+10 kb C>T, c.1161delC, and p.S549N were identified in two patients each and p.R352Q, p.R1158X and p.R75Q were identified in one patient each. Three novel mutations, viz. c.1002-7_1002-5delTTT, p.G149X and p.L183I were also identified. Majority of patients who were p.F508del positive originated from Pakistan and north-western states of India. The phenotypes of all patients were classical. Genotype-phenotype correlation revealed that p.F508del positive patients had a more severe disease, manifesting at an earlier age.

CONCLUSIONS

A strategy for mutation screening for CF in India must involve testing for p.F508del followed by c.1161delC, c.3849+10 kb C>T and p.S549N. There is a need for large multicentric studies using more sensitive techniques for the identification of mutations in Indian CF patients.