[Metabolic bone disease in premature infants and genetic polymorphisms].
Metabolic bone disease is an important complication among infants very-low-birth-weight (< 1500 g). In adults, osteoporosis has been shown to be associated with polymorphisms of vitamin D receptor, estrogen receptor, and collagen Ialpha1 receptor genes.


OBJECTIVE
The primary goal of the study was to investigate the possible association between metabolic bone disease and the allelic polymorphisms of these three genes.


METHODS
104 infants very-low-birth-weight were enrolled to the study. Bone formation (serum alkaline phosphatase, osteocalcin) and bone resorption (urinary excretion of calcium and pyridinium crosslink) markers were determined and x-rays of the chest and wrist (together with the distal portions of associated long bones) were obtained.


RESULTS
Thirty infants (28,8%) were diagnosed with metabolic bone disease based on high activity of bone formation, bone resorption markers, and positive radiologic signs. Statistically significant correlation between thymine-adenine repeat [(TA) n ] allelic variant of estrogen receptor gene and bone disease was observed. Infants with metabolic bone disease more often carried low number of repeats [(TA) n < 19] [odds ratio (OR): 5.82, 95% confidence interval (CI): 2.26-14.98]. Significantly higher number of repeats [(TA)n > 18] was found more frequently in the control group (OR: 0.20, 95% CI: 0.05-0.82). Furthermore significant interaction between vitamin D receptor and collagen Ialpha1 receptor genotypes ( p = 0.023) was observed. In a forward stepwise logistic regression model, bone disorder of preterms correlated with male gender ( p = 0.001), duration of hospitalization ( p = 0.007), homozygous allelic variants of high number of (TA) n repeats ( p = 0.025) and interaction between vitamin D receptor (Tt) and estrogen receptor (homozygous allelic variants of low number of repeats) genotype ( p = 0.037).


CONCLUSIONS
The results suggest that the development of metabolic bone disease in infants very-low-birth-weight may be associated with genetic polymorphisms.
Funke
Simone
S
Pécsi Tudományegyetem, Altalános Orvostudományi Kar Szülészeti és Nogyógyászati Klinika Pécs Edesanyák útja 17. 7624. Simone.funke@aok.pte.hu
Morava
Eva
E
Czakó
Márta
M
Vida
Gabriella
G
Ertl
Tibor
T
Kosztolányi
György
G
D000225:Adenine; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000000981:diagnostic imaging / Q000235:genetics* / Q000378:metabolism* / Q000652:urine; D001862:Bone Resorption; D001842:Bone and Bones / Q000378:metabolism*; D017610:Calcium Compounds / Q000652:urine; D016022:Case-Control Studies; D024042:Collagen Type I / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000378:metabolism* / Q000652:urine; D019102:Infant, Very Low Birth Weight / Q000097:blood / Q000378:metabolism* / Q000652:urine; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D018895:Microsatellite Repeats; D016017:Odds Ratio; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis; D010281:Parathyroid Hormone / Q000097:blood; D011110:Polymorphism, Genetic; D011726:Pyridinium Compounds / Q000652:urine; D011859:Radiography; D018167:Receptors, Calcitriol / Q000235:genetics*; D038981:Receptors, Collagen / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics*; D013941:Thymine; D013997:Time Factors; D014953:Wrist / Q000000981:diagnostic imaging
D015415:Biomarkers; D017610:Calcium Compounds; D024042:Collagen Type I; D010281:Parathyroid Hormone; D011726:Pyridinium Compounds; D018167:Receptors, Calcitriol; D038981:Receptors, Collagen; D011960:Receptors, Estrogen; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D000225:Adenine; D013941:Thymine