European Journal of Biomedical and Pharmaceutical Sciences

SMN GENE DELETIONS ASSESSMENT AND PRENATAL DIAGNOSIS IN FAMILIES OF CHILDREN WITH THE SYNDROME TABRIZ SPINAL ATROPHY – MUSCLE

*Belal Mohammadi and Shahin Asadi

ABSTRACT

Muscle atrophy syndrome - Spinal (SMA) is one of the common diseases of muscle - nerve, with progressive paralysis is due to the alpha motor neuron in the spinal cord becomes waste. SMN1 and SMN2 gene expression in SMA by only a single nucleotide in exon 7 are different. Homozygous deletion of exon 7 in the SMN1 gene is the most common mutation observed. Compound heterozygosity small proportion of patients with a point mutation in one allele and the other allele are removed. In other cases the disease does not appear to be the result of a change in SMN1. In spinal atrophy - muscle, SMN2 unable to compensate for the shortage caused by the deletion of exon 7. The aim of the present study was to estimate the prevalence of common deletion of exon 7 in the SMN1 gene families in Tabriz, in order to determine the status of the carrier and prenatal diagnosis. 119 families with a history of child with SMA and determined that the deletion of exon 7 in the child with the parents were carriers and Also well as 42 cases of prenatal diagnosis for couples fetus was a carrier. Of the families surveyed, 127 families with a history of SMA1, 24 families with a history of type II and 11 families with a history of type III disease who have had children. In families with a history of a patient, 89 families had both parents carry the deletion of exon 7 and in 26 families, one of them was carrying. The frequencies in families with a history of type II SMA 16 and 1, respectively, and in families with a history of type III SMA was 2,3 respectively. Investigation of fetal samples showed that 11 of 63 samples (5.17%) were diagnosed. Except for two, all patients were homozygote for deletion of exon 7 (7.96% of patients). The study showed that molecular analysis of the two alleles of exon 7 SMN1 appropriate method for the removal and reliable diagnosis of patients to determine the carrier and prenatal diagnosis in families with patients with SMA is.

Keywords: SMN1, SMN2, SMA, Exon 7, PCR.