The new CFTR GOLD test includes NGS (Illumina Miseq) testing for the CFTR cystic fibrosis gene at 99.6% or 100% coverage, the 97% coverage at the HBB β-globin gene (point mutations) and the genes of α-globin HBA1 and HBA2 at a coverage rate of about 5% (point mutations). Finally, it includes the control of silent carriers of Spinal Muscular Atrophy, SMN1.
Deletions that usually occur in α-globin, are detected with the MLPA methodology and cover about 95% of the cases of stretcher. The value of α- and β-globin point mutations lies in the fact that "silent" point mutations are detected which are dangerous and "insidious" as they do not cause changes in hemoglobin electrophoresis and can manifest the disease with mild or severe symptoms.
Also, the new CFTR GOLD test includes the control of silent carriers of Spinal Muscular Atrophy. Spinal Muscular Atrophy (NMA) is a serious pediatric disease that causes severe disability in childhood or even death. 90% of cases are due to large deletions of the SMN1 gene (mainly the exons 7 and 8) which are detected by the MLPA method. However, there is a percentage of "silent" carriers of NMA disease, with "2 + 0" genotype, 2 copies of the SMN1 gene in one allele and 0 copies of the SMN1 gene in the second allele.
The MLPA method can NOT detect the "2 + 0" genotype as it cannot distinguish whether the 2 copies are located in the same or different alleles, therefore giving a "normal" result. However, the examinee may have a "2 + 0" genotype, which means that he/she is a silent carrier. In the Caucasian populations the percentage of silent bodies is up to 6%.
The control of the "silent carriers" of Spinal Muscular Atrophy is offered with the new upgraded CFTR GOLD test.