Homozygous autosomal dominant hypercholesterolaemia doubles Lp(a) levels compared to heterozygous carriers, a Dutch study of 119 individuals (J Clin Lipidol 2017)

Original title: Plasma lipoprotein(a) levels in patients with homozygous autosomal dominant hypercholesterolemia

J Clin Lipidol · 1 January 2017 · 7

Sjouke B, Yahya R, Tanck MWT, Defesche JC, de Graaf J, Wiegman A, Kastelein JJP, Mulder MT, Hovingh GK, Roeters van Lennep JE

This Dutch study examined whether Lp(a) levels differ by mutation dose in 119 individuals with autosomal dominant hypercholesterolaemia (ADH), caused by LDLR, APOB or PCSK9 mutations, and their relatives. Among 34 bi-allelic ADH mutation carriers, 63 mono-allelic carriers, and 22 unaffected relatives, median Lp(a) rose from 19.9 mg/dL in unaffected relatives to 24.4 mg/dL in heterozygous LDLR mutation carriers (HeFH) to 47.3 mg/dL in homozygous LDLR carriers (HoFH) (P=.150 for gene-dose dependency). For APOB mutations, median Lp(a) was 50.3 mg/dL in heterozygotes and 205.5 mg/dL in the homozygote (P=.012 for gene-dose dependency). Double heterozygous LDLR/APOB carriers had median Lp(a) of 27.0 mg/dL, not significantly different from homozygous LDLR or APOB patients (P=.730 and .340). The findings show a trend toward higher Lp(a) in homozygous ADH patients compared with heterozygous carriers and unaffected relatives, raising the question of whether this adds to their cardiovascular risk.

Original abstract

Background: Patients with autosomal dominant hypercholesterolemia (ADH), caused by mutations in either low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin-kexin type 9 (PCSK9) are characterized by high low-density lipoprotein cholesterol levels and in some studies also high lipoprotein(a) (Lp(a)) levels were observed. The question remains whether this effect on Lp(a) levels is gene-dose-dependent in individuals with either 0, 1, or 2 LDLR or APOB mutations.

Objective: We set out to study whether Lp(a) levels differ among bi-allelic ADH mutation carriers, and their relatives, in the Netherlands.

Methods: Bi-allelic ADH mutation carriers were identified in the database of the national referral laboratory for DNA diagnostics of inherited dyslipidemias. Family members were invited by the index cases to participate. Clinical parameters and Lp(a) levels were measured in bi-allelic ADH mutation carriers and their heterozygous and unaffected relatives.

Results: We included a total of 119 individuals; 34 bi-allelic ADH mutation carriers (20 homozygous/compound heterozygous LDLR mutation carriers (HoFH), 2 homozygous APOB mutation carriers (HoFDB), and 12 double heterozygotes for an LDLR and APOB mutation), 63 mono-allelic ADH mutation carriers (50 heterozygous LDLR [HeFH], 13 heterozygous APOB [HeFDB] mutation carriers), and 22 unaffected family members. Median Lp(a) levels in unaffected relatives, HeFH, and HoFH patients were 19.9 (11.1-41.5), 24.4 (5.9-70.6), and 47.3 (14.9-111.7) mg/dL, respectively (P = .150 for gene-dose dependency). Median Lp(a) levels in HeFDB and HoFDB patients were 50.3 (18.7-120.9) and 205.5 (no interquartile range calculated), respectively (P = .012 for gene-dose-dependency). Double heterozygous carriers of LDLR and APOB mutations had median Lp(a) levels of 27.0 (23.5-45.0), which did not significantly differ from HoFH and HoFDB patients (P = .730 and .340, respectively).

Conclusion: A (trend toward) increased plasma Lp(a) levels in homozygous ADH patients compared with both heterozygous ADH and unaffected relatives was observed. Whether increased Lp(a) levels in homozygous ADH patients add to the increased cardiovascular disease risk and whether this risk can be reduced by therapies that lower both low-density lipoprotein cholesterol and Lp(a) levels remains to be elucidated.

Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.