Table 1.

Molecular Genetic Testing Used in Smith-Lemli-Opitz Syndrome

Gene 1MethodProportion of Probands with a Pathogenic Variant 2 Detectable by Method
DHCR7 Sequence analysis 396% 4, 5
Gene-targeted deletion/duplication analysis 6<4% 7
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 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.

4.
5.

Most of the affected individuals studied have two detectable pathogenic variants; rare individuals had only one detectable pathogenic variant [Waterham & Hennekam 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.

7.

From: Smith-Lemli-Opitz Syndrome

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