epidemiology and diagnosis of smas in iran

spinal muscular atrophies (smas) are one of the more common autosomal recessive and single gene disorders. they are heterogeneous disorders, both in phenotypic and genotypic aspects. prevalence of these disorders are about 1 of every 6000 to 25000 live born babies in different ethnicities. in some chinese population prevalence of disease reported to be 1 in 50000. if it was true, carrier frequency would be about 1 of every 40 to 80 person. around 94 percent of affected individuals showed deletion in both copies of exon 7 of smn1 gene. it can also be due to smn gene conversion and changing to smn2 copy in some patients. according to our knowledge there are no extensive epidemiological studies in iranian population yet. so, our knowledge is deficient regarding the frequency of disease and carriers. because of the high rate of consanguineous marriages in our population, frequency of smas should be high. in this study we proposed to delineate incidence and carrier frequency, clinical aspects, and consanguinity rate in the affected sma1 families. also we preformed molecular analysis, and detected the mutations in the smn gene. in a 2 years period from the bahman 1384 to bahman 1386, 30734 live born babies in six collaborative hospitals evaluated. four babies affected to sma1 have been detected. so in our study the incidence of disease was 1 in 7683 and carrier frequency was 1 in 43