Johns Hopkins DNA Diagnostic
Informed consent from the patient is required prior to ordering a
genetic test. The DNA Diagnostic Lab's consent is located on the
second page of the requisition form. There is also a patient
brochure, "Things Every Patient Should
Know Before Consenting to a Genetic Test", available for
||Genotyping for rs4238001 (c.4G>A; p.Gly2Ser); Direct mutation analysis by DNA
sequencing of SCARB1 exon
||83891 x 1;
83898 x 1;
83904 x 2;
83909 x 2;
83912 x 1
2013 CPT Code: 81479
rs4238001 variant has been shown to account for 16% of SR-B1
protein level variation among individuals with HDL-C>60mg/dl
(West et al, 2009, J Clin Endocrinol Metab, 94:1451). Though
the frequency varies by ethnicity, approximately 13% of the
population are carriers
||$302 per individual blood sample
Considerations/ Clinical Utility
is the predominant receptor for HDL cholesterol. It plays
an important role in reverse cholesterol transport (removal from
cells and eventual disposal via the liver) and is highly
expressed in the liver and steroidogenic tissues.
rs4238001 is associated
with SR-B1 deficiency, and is considered a risk or
susceptibility allele for elevated HDL-C. Elevated HDL-C
is typically thought to have a protective effect against
cardiovascular disease in the face of elevated LDL-C; however,
there is a subset of individuals with elevated HDL-C who remain
at risk for cardiovascular disease.
If HDL-C is elevated
because of SR-B1 deficiency, this protective effect is
diminished. In this patient population, it is therefore
advisable to consider treatment with cholesterol lowering
medications to an appropriate LDL-C target.
Link to Requisition and
Link to clinical information on Pfeiffer Syndrome.
Link to Patient and Family
Page for general resources on genetic testing.