Related Experiment Videos
The relationship between genotype and exercise tolerance in children with cystic fibrosis
Hiran C Selvadurai1, Karen O McKay, Cameron J Blimkie
1Children's Chest Research Centre, Department of Respiratory Medicine, Children's Hospital Institute of Sports Medicine, The Children's Hospital at Westmead, New South Wales, Australia. hiran.selvadurai@sickkids.ca
Insights
Children with cystic fibrosis (CF) and specific CFTR mutations show varying fitness levels. Genotype impacts aerobic capacity and anaerobic power, but not lung function, in CF patients.
Area of Science:
- Genetics
- Pediatrics
- Exercise Physiology
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs.
- The DeltaF508 mutation is common in CF patients.
- CFTR protein dysfunction underlies CF pathogenesis.
Purpose of the Study:
- To investigate the relationship between CF genotype and physical fitness in children.
- To determine if CFTR mutation class correlates with aerobic capacity and anaerobic power.
Main Methods:
- Genotyping classified CF patients based on the second CF mutation.
- Peak aerobic capacity measured via modified Bruce treadmill protocol.
- Peak anaerobic power assessed using the Wingate cycle ergometer test.
Main Results:
- Patients with Class I/II CFTR mutations had significantly lower peak aerobic capacity compared to Class III.
- Children with Class IV/V CFTR mutations exhibited higher peak anaerobic power than Class I, II, or III.
- No significant differences in lung function (FEV1) were observed across CFTR mutation classes.
Conclusions:
- CF genotype is statistically related to specific fitness measures in children.
- Mechanisms linking CFTR mutation class to fitness variations require further investigation.
Abstract:
The relationship between fitness and genotype in children with cystic fibrosis (CF) and at least one copy of the DeltaF508 mutation was examined. Genotype was classified according to the second CF mutation. Fitness was measured by peak aerobic capacity (using a modified Bruce protocol during treadmill exercise) and anaerobic power (using the Wingate test on a cycle ergometer). The class of cystic fibrosis transmembrane regulator proteins (CFTR) mutation was statistically related with aerobic capacity, peak anaerobic power, body mass index, lung function (forced expiratory volume in one second), and disease severity as measured by the Shwachman score. Patients with mutations causing defective CFTR production (Class I) or processing (Class II) had a significantly lower peak aerobic capacity (28.6 +/- 4.2 ml/kg/min and 31.7 +/- 5.4 ml/kg/min, respectively) than those with a mutation conferring defective regulation of CFTR (Class III) (43.9 +/- 6.4 ml/kg/min). The peak anaerobic power in subjects with mutations inducing decreased CFTR conduction (Class IV) or CFTR mRNA (Class V), were significantly higher (11.4 +/- 1.7 and 11.6 +/- 1.5 watts/kg, respectively) than children with Class I (9.7 +/- 1.4 watts/kg), Class II (9.8 +/- 1.4 watts/kg), or Class III (10.5 +/- 1.8 watts/kg) mutations. There were no statistically significant differences in the lung function of patients with the different mutations. These results indicate a relationship between CF genotype and some measures of fitness, the mechanisms of which remain to be determined.