Increased susceptibility to complicated pneumonia among Egyptian
children with FokI (rs2228570), not TaqI (rs731236), Vitamin D receptor
gene polymorphism in association with vitamin D deficiency
Abstract
Introduction: Determining genetic contribution to development
of complicated community-acquired pneumonia in children may help
understand underlying pathogenesis. We aimed to investigate the
association between two vitamin D receptor (VDR) gene polymorphisms,
FokI and TaqI, and susceptibility to complicated pneumonia in Egyptian
children compared to uncomplicated pneumonia, also associations with 25
hydroxy-vitamin D serum level were studied. Methods: This was a
case-control study that included 320 participants divided into 2 groups:
patients and controls. The patients’ group included 100 children
hospitalized with complicated pneumonia and 100 with uncomplicated
pneumonia. 120 age and sex-matched apparently healthy children served as
controls. The VDR FokI and TaqI polymorphisms were genotyped using
polymerase chain reaction-restriction fragment length polymorphism
(PCR-RFLP) technique. 25 hydroxy-vitamin D level was estimated in serum
using ELISA. Results: Regarding FokI, Homogenous FF genotype
was more common in complicated (52%) and uncomplicated pneumonia (28%)
than controls (10%) (OR=65; 95%CI (5.13-822.63), p<0.001)
and (OR=4.3; 95%CI (0.7-27.16), p=0.003), respectively. Children
carrying F allele possessed 3 higher odds for complicated than
uncomplicated pneumonia (OR=3.08; 95%CI (1.33-7.14),
p<0.001). Heterogenous Ff genotype increased susceptibility to
complicated pneumonia (OR=13.7; 95%CI (4.6-40.1), p<0.001),
not uncomplicated pneumonia (OR=1.56; 95%CI (0.86-2.85), p=0.145).
Among complicated pneumonia, vitamin D level was lower in FF
(6.92±2.6ng/ml) than Ff (9.55±3.2 ng/ml) and ff genotype carriers
(13.13±3.6ng/ml) (p<0.001). There was no significant
difference between patients and controls as regards TaqI genotypes and
alleles. Conclusion: In association with vitamin D deficiency,
VDR gene FokI polymorphism, not TaqI, is a genetic risk factor for
complicated pneumonia in Egyptian children.