POLYMORPHISMS OF GENES ASSOCIATED TO BONE MINERAL DENSITY IN SMALL FOR GESTATIONAL AGE CHILDREN

PEREZ A, PICOTTO G,SILVANO L, MUÑOZ L, DIAZ DE BARBOZA G Y COL

Rosario

Congreso; XXIII Reunión Anual de la Asociación Argentina de Osteología y Metabolismo Mineral; 2006

AAOMM

Small for gestational age children (SGA) constitute a group of children with low weight at birth, below 2 standard deviation of the mean weight expected for their gestational age. About 15 % of them do not recover growth (SGA without catch up, SGA -CU), while the others do (SGA with catch up, SGA +CU) during the first two years of age. In a previous work, we have demonstrated that SGA show alterations in the IGF system and lower bone mineral density (BMD) as compared to matched control children. Due that BMD is determined by genetic factors, the aim of the present work was to study the polymorphism distribution of genes such as vitamin D receptor (VDR), estrogen receptor (ER) and colagen type 1 subunit á (COLIA1), and the probable association of these genotypes with BMD. Ninety eight children were studied, 48 controls, 23 SGA+CU and 26 SGA-CU. Mean chronological age was 7.5 y., 7.0 y. (SGA+/CU) and 6.0 y. (SGA-/CU) (p = 0,099).  Blood was obtained, DNA was isolated and the different genotypes were determined by using specific primers and RFLP technique. For VDR, Bsm I and Fok I were used as restrictases, for ER were used Pvu II and Xba I, and Bal I for the COLIA1 gene. Data indicate that the polymorphism distribution for VDR and ER genotypes was similar in the 3 groups. Regarding the COLIA1 gene, the genotype SS in SGA ?CU was 72 % versus 53 % (controls) and 59% (SGA+CU). SS genotype in SGA ?CU was associated with the lowest BMD either in lumbar spine or femoral neck. In conclusion, COLIA1 polymorphism may be a useful predictor of low BMD in SGA-CU.