1
|
Zhou Y, Jiang Y. Current Advances in Genetic Testing for Spinal Muscular Atrophy. Curr Genomics 2023; 24:273-286. [PMID: 38235355 PMCID: PMC10790334 DOI: 10.2174/0113892029273388231023072050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/22/2023] [Accepted: 10/02/2023] [Indexed: 01/19/2024] Open
Abstract
Spinal muscular atrophy (SMA) is one of the most common genetic disorders worldwide, and genetic testing plays a key role in its diagnosis and prevention. The last decade has seen a continuous flow of new methods for SMA genetic testing that, along with traditional approaches, have affected clinical practice patterns to some degree. Targeting different application scenarios and selecting the appropriate technique for genetic testing have become priorities for optimizing the clinical pathway for SMA. In this review, we summarize the latest technological innovations in genetic testing for SMA, including MassArray®, digital PCR (dPCR), next-generation sequencing (NGS), and third-generation sequencing (TGS). Implementation recommendations for rationally choosing different technical strategies in the tertiary prevention of SMA are also explored.
Collapse
Affiliation(s)
- Yulin Zhou
- United Diagnostic and Research Center for Clinical Genetics, Women and Children’s Hospital, School of Medicine & School of Public Health, Xiamen University, Xiamen, Fujian 361003, P.R. China
- Biobank, Women and Children’s Hospital, School of Medicine, Xiamen University, Xiamen, Fujian 361003, P.R. China
| | - Yu Jiang
- United Diagnostic and Research Center for Clinical Genetics, Women and Children’s Hospital, School of Medicine & School of Public Health, Xiamen University, Xiamen, Fujian 361003, P.R. China
- Biobank, Women and Children’s Hospital, School of Medicine, Xiamen University, Xiamen, Fujian 361003, P.R. China
| |
Collapse
|
2
|
Tan J, Zhang J, Sun R, Jiang Z, Wang Y, Ma D, Jiao J, Chen H, Lin Y, Zhang Q, Xu Z, Hu P. Evaluating the performance of four assays for carrier screening of spinal muscular atrophy. Clin Chim Acta 2023; 548:117496. [PMID: 37479010 DOI: 10.1016/j.cca.2023.117496] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/19/2023] [Accepted: 07/18/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND AND AIMS Spinal muscular atrophy (SMA) is an autosomal recessive inherited neuromuscular condition caused by biallelic mutations in the survival of motor neuron 1 (SMN1) gene. A homozygous deletion of the SMN1 gene accounts for approximately 95-98% of SMA patients. A highly homologous gene survival motor neuron 2 (SMN2) can partially compensate for SMN1 deletion, and its copy number is associated with disease severity. Population-based carrier screening by simultaneous quantification of SMN1 and SMN2 copy numbers is the best method to prevent SMA. MATERIALS AND METHODS In this study, a total of 516 samples were re-tested for the SMN1 copy number by using quantitative polymerase chain reaction (qPCR), multiplex ligation probe amplification (MLPA), droplet digital PCR (ddPCR), high-resolution melting (HRM) analysis, and PCR-based capillary electrophoresis (PCR/CE) simultaneously. Then, the performance of these methods was compared by using MLPA results as the reference. RESULTS The results of qPCR, ddPCR, HRM, and PCR/CE in detecting heterozygous deletion of SMN1 exon 7 and the results of ddPCR, HRM, and PCR/CE in detecting ≥2 copies of SMN1 exon7 are totally consistent with those of MLPA. The sensitivity and specificity of qPCR for detection of 2 copies of SMN1 exon 7 were 99.7% and 98.8%, respectively. The sensitivity and specificity of qPCR for detection of >2 copies of SMN1 exon 7 were 96.3% and 99.8%, respectively. Compared with the MLPA results, the sensitivity and specificity of qPCR and HRM for detection of heterozygous deletion of SMN1 exon 8 were 100% and 100%, respectively. They were 99.4% and 100%, respectively for detection of 2 copies, and 100% and 100%, respectively for detection of >2 copies. The results of PCR/CE in detecting SMN1 exon 8 were consistent with those of MLPA. CONCLUSION All these four methods show excellent performance in detecting heterozygous deletion of SMN1 exon 7. All PCR/CE results are totally concordant with those of MLPA. As the most cost-effective method, qPCR also shows high sensitivity and specificity in detecting SMN1. Taken together, our study provides useful information to select appropriate methods for SMA carrier screening.
Collapse
Affiliation(s)
- Jianxin Tan
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Jingjing Zhang
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Ruihong Sun
- Department of Laboratory Medicine, The First School of Clinical Medicine, Nanjing Medical University, Nanjing 210029, People's Republic of China
| | - Zhu Jiang
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Yuguo Wang
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Dingyuan Ma
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Jiao Jiao
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Hao Chen
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Yingchun Lin
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Qinxin Zhang
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China
| | - Zhengfeng Xu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China.
| | - Ping Hu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, People's Republic of China.
| |
Collapse
|
3
|
Eissa NR, Hassan HA, Senousy SM, Soliman HN, Essawi ML. SMA carrier testing using Real-time PCR as a potential preconception screening tool. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00233-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background
SMA is a neuromuscular genetic disorder causing irreversible degeneration of the anterior horn cells of lower motor neurons. According to the age of onset and severity of the condition, it is classified into 5 subtypes. SMA carrier’s frequency worldwide is 1:40–80. We used quantitative real-time PCR to determine the copy number of the disease-determining SMN1 gene by rapid and reliable assays. We studied the SMN1 gene copy number in Egyptian sample of 115 individuals, as well as in 10 SMA families.
Results
Our results showed that 57.4% of the couples with the previous history of an affected family members were carriers. On the individual level, carriers of single SMN1 gene copy rate are much higher than the previously reported frequency rates. The effect of consanguineous marriages appears evident in SMA as an autosomal recessive disorder.
Conclusions
In conclusion, the carrier frequency detected in our cohort was high, which possibly corresponds with the worldwide report of SMA as a leading genetic cause of death among infants. Considering the high rate of consanguinity in developing countries confirms the importance of national SMA carrier screening in Egypt. The qPCR carrier screening test is a rapid-cost effective test that can detect approximately 90% of carriers. A population-based preconception prenatal screening for couples will also help reduce the disease burden.
Collapse
|