Table 1.

Molecular Genetic Testing Used in MECP2 Duplication Syndrome

Gene 1MethodProportion of Probands with a Pathogenic Variant 2 Detectable by Method
MECP2 Gene-targeted duplication analysis 3100% 4
CMA 5100% 6
1.

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

2.

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

3.

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.

4.

Duplications ranging from 0.3 to 4 Mb are found in 100% of affected males [Van Esch et al 2005, del Gaudio et al 2006, Smyk et al 2008, Clayton-Smith et al 2009, Lugtenberg et al 2009]. The duplications occur in the chromosome region Xq28, which includes all of MECP2.

5.

Chromosomal microarray analysis (CMA) uses oligonucleotide or SNP arrays to detect genome-wide large deletions/duplications (including MECP2) that cannot be detected by sequence analysis. The ability to determine the size of the deletion/duplication depends on the type of microarray used and the density of probes in the Xq28 region. CMA designs in current clinical use target the Xq28 region.

6.

From: MECP2 Duplication Syndrome

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