Table 1.

Molecular Genetic Testing Used in X-Linked Infantile Spinal Muscular Atrophy

Gene 1MethodProportion of Pathogenic Variants 2 Identified by Method
UBA1 Sequence analysis 39/9 4
Gene-targeted deletion/duplication analysis 5Unknown 6
1.

See Table A. Genes and Databases for chromosome locus and protein.

2.

See Molecular Genetics for information on variants detected in this gene.

3.

Sequence analysis detects variants that are benign, likely benign, of uncertain significance, likely pathogenic, or pathogenic. Variants may include missense, nonsense, and splice site variants and small intragenic deletions/insertions; typically, exon or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.

4.

To date, eight families and one simplex individual have been detected with UBA1 pathogenic variants [Dressman et al 2007, Ramser et al 2008, Dlamini et al 2013, Jędrzejowska et al 2015, Shaughnessy et al 2020, Wang et al 2020].

5.

Gene-targeted deletion/duplication analysis detects intragenic deletions or duplications. Methods used may include a range of techniques such as quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and a gene-targeted microarray designed to detect single-exon deletions or duplications.

6.

No data on detection rate of gene-targeted deletion/duplication analysis are available. To date, all pathogenic variants reported have been missense variants [Balak et al 2017].

From: Spinal Muscular Atrophy, X-Linked Infantile

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