<prompt> Answer this question truthfullyCould you please provide me with the original text that needs to be rephrased?  <response>: <reason> Incidence of SMA 1 in 6,000 10,000 live births or 7.8-10 per 100,000 live births.Carrier frequency for SMN 1 gene mutation is 1:38 to 1:50. , , , 7.5 million Americans are carriers.A 2005 study in Cuba found a reduced incidence of Type I SMA amongst the Cuban population overall, 3.53 per 100,000 live births and especially amongst those of African ancestry 0.89 to 0.93 per 100,000 live births . 