Diagnosis of familial hypercholesterolemia in general practice using clinical diagnostic criteria or genetic testing as part of cascade genetic screening.
BACKGROUND
Too few familial hypercholesterolemia (FH) patients are diagnosed. The most cost-effective strategy to diagnose FH is to examine first-degree relatives of already diagnosed patients. This is referred to as cascade genetic screening.


RESULTS
One thousand eight hundred and five first-degree relatives of index patients with molecularly defined FH consented to cascade genetic screening by the use of molecular genetic testing. Of these, 44.8% were mutation carriers and 55.2% were noncarriers. Only 44.2% of the mutation carriers were on lipid-lowering drugs at the time of genetic testing. Of these, only 9.4% had a value for total serum cholesterol below 5 mM. Among adult mutation carriers who were not on lipid-lowering treatment at the time of genetic testing, reductions in total serum cholesterol and low-density lipoprotein cholesterol of 18.4% (p < 0.0001) and 25.3% (p < 0.0001), respectively, were observed 6 months after genetic testing. It is assumed that this improvement in the lipid profile is due to a definite diagnosis obtained by molecular genetic testing. By using the results of genetic testing as the gold standard for diagnosis of FH, data from a questionnaire filled out by the relatives showed that the use of clinical criteria to diagnose FH in general practice had a sensitivity of 46.2% and a specificity of 88.0%.


CONCLUSIONS
The use of clinical diagnostic criteria to diagnose FH in general practice identifies only approximately 50% of FH patients. Molecular genetic testing as part of cascade genetic screening is an efficient tool to diagnose patients, leading to significant improvement in the lipid profile. It should therefore be implemented in clinical medicine.
Leren
Trond P
TP
Medical Genetics Laboratory, Department of Medical Genetics, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway. trond.leren@rikshospitalet.no
Finborud
Tora Himle
TH
Manshaus
Turid E
TE
Ose
Leiv
L
Berge
Knut Erik
KE
D000328:Adult; D004252:DNA Mutational Analysis; D005091:Exons; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009664:Norway; D013997:Time Factors