Table 1.

Molecular Genetic Testing Used in Pyridoxine-Dependent Epilepsy – ALDH7A1

Gene 1MethodProportion of Pathogenic Variants 2 Detectable by Method
ALDH7A1 Sequence analysis 3>95% 4, 5
Gene-targeted deletion/duplication analysis 6<5% 4
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.

Data derived from Coughlin et al [2019] and the subscription-based professional view of Human Gene Mutation Database [Stenson et al 2020]

5.

Deep intronic variants may be missed by sequence analysis that includes exons and flanking regions only. ALDH7A1 variant c.696-502G>C results in introduction of a cryptic acceptor splice site, activation of a cryptic donor splice site, and introduction of a pseudoexon between exons 7 and 8 [Milh et al 2012].

6.

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.

From: Pyridoxine-Dependent Epilepsy – ALDH7A1

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