Spectrum of mutations in homozygous familial hypercholesterolemia in India, with four novel mutations

BACKGROUND AND AIMS

Homozygous familial hypercholesterolemia (FH) is a rare but serious, inherited disorder of lipid metabolism characterized by very high total and LDL cholesterol levels from birth. It presents as cutaneous and tendon xanthomas since childhood, with or without cardiac involvement. FH is commonly caused by mutations in three genes, i.e. LDL receptor (LDLR), apolipoprotein B (ApoB) and PCSK9. We aimed to determine the spectrum of mutations in cases of homozygous FH in Asian Indians and evaluate if there was any similarity to the mutations observed in Caucasians.

METHODS

Sixteen homozygous FH subjects from eleven families were analyzed for mutations by Sanger sequencing. Large rearrangements in LDLR gene were evaluated by multiplex ligation probe dependent amplification (MLPA) technique.

RESULTS

Ten mutations were observed in LDLR gene, of which four mutations were novel. No mutation was detected in ApoB gene and common PCSK9 mutation (p.D374Y). Fourteen cases had homozygous mutations; one had compound heterozygous mutation, while no mutation was detected in one clinically homozygous case. We report an interesting "Triple hit" case with features of homozygous FH.

CONCLUSIONS

The spectrum of mutations in the Asian Indian population is quite heterogeneous. Of the mutations identified, 40% were novel. No mutation was observed in exons 3, 9 and 14 of LDLR gene, which are considered to be hot spots in studies done on Asian Indians in South Africa. Early detection followed by aggressive therapy, and cascade screening of extended families has been initiated to reduce the morbidity and mortality in these patients.

JCL roundtable: drug treatment of severe forms of familial hypercholesterolemia

Clinical lipidologists are often asked to manage patients with severely elevated low-density lipoprotein cholesterol (LDL-C) and other apolipoprotein B-containing lipoproteins. Statins at maximum doses and in combination with other drugs may not achieve adequate reductions in LDL-C in such patients. The most dramatic elevations are usually in patients with genetic abnormalities in the LDL receptor gene on both chromosome pairs. LDL-C values well in excess of 400 mg/dL are not fully responsive to current treatments. In the past few months, the Food and Drug Administration has approved 2 new drugs for special use in such patients; these are mipomersen and lomitapide. During the National Lipid Association's Scientific Sessions, 2 highly experienced clinician scientists who have completed research studies with these agents agreed to answer questions pertinent to the prescription use of these agents. These scientists are Dr Anne Goldberg from Washington University in St. Louis and Dr Daniel Rader from the University of Pennsylvania.

Should Familial Hypercholesterolaemia Be Included in the UK Newborn Whole Genome Sequencing Programme?

PURPOSE OF REVIEW

The UK National Health Service (NHS) has recently announced a Newborn Genomes Programme (NGP) to identify infants with treatable inherited disorders using whole genome sequencing (WGS). Here, we address, for familial hypercholesterolaemia (FH), the four principles that must be met for the inclusion of a disorder in the NGP.

RECENT FINDINGS

Principle A: There is strong evidence that the genetic variants causing FH can be reliably detected. Principle B: A high proportion of individuals who carry an FH-causing variant are likely to develop early heart disease if left undiagnosed and not offered appropriate treatment. Principle C: Early intervention has been shown to lead to substantially improved outcomes in children with FH. Principle D: The recommended interventions are equitably accessible for all. FH meets all the Wilson and Jungner criteria for inclusion in a screening programme, and it also meets all four principles and therefore should be included in the Newborn Genomes Programme.

Real-world experience of long-term efficacy and safety of evinacumab in patients with homozygous familial hypercholesterolemia treated and untreated with lipoprotein apheresis

BACKGROUND

Evinacumab is an inhibitor of angiopoietin-like 3 protein (ANGPTL3) that offers a new approach for correcting high low-density lipoprotein-cholesterol (LDL-C) and may reduce the need or frequency for lipoprotein apheresis (LA) in patients with homozygous familial hypercholesterolemia (HoFH).

OBJECTIVE

We aimed to investigate the long-term efficacy and safety of evinacumab in patients with HoFH aged between 14 and 63 years on and off LA in real-world clinical practice.

METHODS

Evinacumab was administrated intravenously (15 mg /kg every 4 weeks) for the first 24 months in 7 patients with genetically confirmed HoFH, receiving best standard of lipid-lowering treatment and LA, followed by a subsequent compassionate extension period of approximately 12-month treatment with evinacumab without LA. Patient experience of evinacumab and health-related EuroQol (EQ-5D-3L) quality of life questionnaire were also assessed.

RESULTS

Compared with baseline, evinacumab resulted in sustained reductions in plasma LDL-C concentration of -43.4% and -54.2% at 30 and 36 months, respectively. All 7 HoFH patients achieved an LDL-C reduction >30% with 3 patients having on-treatment LDL-C level < 2.5 mmol/L (96 mg/dL). Evinacumab was well-tolerated, with no major adverse events reported or significant changes in liver enzyme concentrations. All FH patients agreed that evinacumab was acceptable and less physically demanding than LA. The mean EQ- utility score and visual analogue score were 0.966 and 78.6, respectively, which are comparable to the Italian general population.

CONCLUSIONS

Our findings suggest that evinacumab is a safe and effective treatment for high LDL-C that is acceptable to HoFH patients receiving and not receiving LA.