Smith-Lemli-Opitz Syndrome
DHCR7 gene sequencing 

(full coding

Lab method: Sanger sequencing

TAT: 2-4 weeks

Specimen requirements: 2-4 ml of blood with anticoagulant EDTA

1 µg DNA in TE, AE or pure sterile water at 100-250 ng/µl
The A260/A280 ratio should be 1.8-2.0. DNA sample should be run on an agarose gel as a single band, showing no degradation, alongside with a quantitative DNA marker.

Ordering information: Go to online ordering or download sample submission form

Indications for genetic testing:

1. Confirmation of clinical diagnosis
2. Carrier testing for at-risk family members
3. Genetic counseling
4. Prenatal diagnosis for known familial mutation

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessively inherited multiple malformation syndrome due to an inborn error cholesterol synthesis – insufficiency of enzyme 7-dehydroxycholesterol reductase. The syndrome is characterized by intrauterine and also postnatal growth retardation, moderate to severe mental retardation, malformations in many organ systems (cardiovascular, urogenital, gastrointestinal and central nervous systems). The patients have a characteristic appearance: ptosis, polydactyly, syndactyly of the II and III toes on both feet.

The incidence of SLOS is 1:20,000-70,000. SLOS is associated with mutations in the DHCR7 gene.

For further information:

Genetic assessment following increased nuchal translucency and normal karyotype
Pergament E, Alamillo C, Sak K, Fiddler M.
Prenat Diagn. 2011 Mar;31(3):307-10. doi: 10.1002/pd.2718. Epub 2011 Feb 15.