Table 1.

Molecular Genetic Testing Used in Acute Intermittent Porphyria

Gene 1MethodProportion of Probands with a Pathogenic Variant 2 Detectable by Method
HMBS Sequence analysis 396%-98% 4
Gene-targeted deletion/duplication analysis 5~2% 4, 6
1.
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 from Cerbino et al [2015] and the subscription-based professional view of Human Gene Mutation Database [Stenson 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. Exome and genome sequencing may be able to detect deletions/duplications using breakpoint detection or read depth; however, sensitivity can be lower than gene-targeted deletion/duplication analysis.

6.

Larger deletions/duplications/insertions and whole-gene deletions have been reported. These will not be detected by single-gene sequencing but may be identified by gene-targeted deletion/duplication analysis or next-generation sequencing.

From: Acute Intermittent Porphyria

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