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Review of Spinal Muscular Atrophy (SMA) for Prenatal and Pediatric Genetic Counselors

  • Review Paper
  • Published:
Journal of Genetic Counseling

Abstract

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular condition with degeneration of the anterior horn cells in the spinal column. Five SMA subtypes exist with classification dependent upon the motor milestones achieved. Study of the SMN1 (survival motor neuron) and SMN2 genes as well as the concepts of the “2 + 0” carriers, gene conversion, de novo mutations and intragenic mutations allow for a better understanding of SMA. Detailing the carrier and diagnostic testing options further deepens the genetic counselor’s knowledge of SMA. A review of care guidelines and research options is included as this information gives a patient a well-rounded view of SMA. Although SMA is most commonly associated with the SMN1 gene, a number of spinal muscular atrophies not caused by genetic changes in this gene may be included as differential diagnoses until confirmatory testing can be completed. SMA is a complex condition requiring a detailed knowledge on the genetic counselor’s part in order to explain the disorder to the patient with clarity thus facilitating increased communication and decision making guidance with the patient.

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Acknowledgments

We would like to thank Kenny Wong, Meghan Wayne, Patricia Page and Natalie Beck for their help in gathering data for this paper. We also gratefully thank Dr. Alan Donnenfeld and Dr. Geraldine McDowell for their review of this manuscript.

Compliance with Ethical Standards

Please refer to this section which is located on page 33. It contains the conflict of interest statements, research involving human/animal participants’ statement, and the informed consent statement.

Conflict of Interest

Amanda Carré declares that she has no conflict of interest.

Candice Empey was a past employee of Integrated Genetics, Laboratory Corporation of America® Holdings, which performs Spinal Muscular Atrophy testing.

Research Involving Human Participants and/or Animals

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed Consent

As this article does not contain any studies with human participants or animals, informed consent was not necessary to obtain.

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This manuscript is submitted solely to the Journal of Genetic Counseling and has not been published elsewhere or submitted to any other journal for publication purposes.

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Authors and Affiliations

  1. Department of Obstetrics and Gynecology, Drexel University College of Medicine, 216 N. Broad St, Feinstein Building 4th Floor, MS 990, Philadelphia, PA, 19102, USA

    Amanda Carré

  2. Integrated Genetics, Laboratory Corporation of America® Holdings, Philadelphia, PA, USA

    Candice Empey

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  1. Amanda Carré
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Correspondence to Amanda Carré.

Additional information

We began our research for this paper by conducting multiple PubMed searches. These searches were completed to locate papers included in the reference section. Keyword combinations utilized during the searches included: spinal muscular atrophy, spinal muscular atrophy carrier screening, and spinal muscular atrophy diagnostic testing. No publishing date limitations were used during the searches. A review of the reference sections in the papers found through the PubMed searches allowed for the collection of additional publications. Finally, a search for spinal muscular atrophy on GeneTests (http://www.genetests.org/ ) demonstrated numerous differential diagnoses for spinal muscular atrophy as caused by changes in the SMN1 gene.

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Appendices

Appendix A

Fig. 1
figure 1

Prenatal general population carrier screen flowchart

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Appendix B

Fig. 2
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Pediatric diagnostic testing flowchart

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Carré, A., Empey, C. Review of Spinal Muscular Atrophy (SMA) for Prenatal and Pediatric Genetic Counselors. J Genet Counsel 25, 32–43 (2016). https://doi.org/10.1007/s10897-015-9859-z

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