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

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

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

The denominator represents only those individuals in the literature who have undergone sequence analysis of ASXL1; some clinically diagnosed individuals whose information has been published have not undergone molecular genetic testing.

Somatic mosaicism for ASXL1 variants, including BOS-associated variants, may be found in the elderly or in other non-BOS cohorts (i.e., cohorts of individuals with cancer); such variants may be reported in reference databases, leading to misclassification of potentially pathogenic variants [Carlston et al 2017]. See Molecular Genetics.

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

No data on detection rate of gene-targeted deletion/duplication analysis are available.

In four individuals with features suggestive of BOS molecular genetic testing of ASXL1 failed to identify a pathogenic variant [Brunner et al 2000, Hastings et al 2010, Hastings et al 2011, Hoischen et al 2011]. It is unclear if these individuals have a different genetic syndrome with clinical features overlapping those of BOS. Greenhalgh et al [2003] reported two sibs with clinical features of BOS in whom a different diagnosis was subsequently confirmed [Bruel et al 2017].