For carrier screening, false negative results can be obtained that the presence of two SMN1 copies on 1 chromosome and 0 on the other, or intragenic mutations in either SMN1 gene.

• 如果做带因者的筛检，二个SMN1基因在同一条染色体或是SMN1基因内有突变的情形将导致筛检结果呈现伪阴性。