Management and clinical outcomes of patients with homozygous familial hypercholesteremia in Saudi Arabia.

We report the incidence, patient characteristic with clinical outcomes in patients with homozygous familial hypercholesterolemia (HoFH) in Saudi Arabia. This is a retrospective and prospective, single center study which included 37 patients 14 years and older enrolled and followed up between 2018-2021 for three years. 46% were females, 78% were offspring of consanguineous marriage. LDLR mutation was in 78% and LDL-C/LDLRAP in 3% of patients. Mean LDL-C at the first presentation was 14.2±3.7 mmol/L, average Dutch lipid score was 20.9±6.24. LDL apheresis was performed on 70% of patients. Most patients were on ezetimibe (92%), high-dose statins ( 84%) and  PCSK9 inhibitors (32%). 48.6% had aortic stenosis, out of which 30% had severe aortic stenosis. Ten underwent aortic valve surgery (5 mechanical valve, 3 Ross procedure, 1 aortic valve repair, 1 bioprosthetic valve) and one had transcatheter aortic valve implantation (TAVI). Coronary artery bypass surgery (CABG) was performed on 32% and percutaneous intervention (PCI) on 11% of patients. HoFH patients have complex diseases with high morbidity and mortality, and benefit from a highly specialized multidisciplinary clinic to address their clinical needs. Although there are several therapeutic agents on the horizon, early diagnosis, and treatment of HoFH remain critical to optimize patient outcomes.

Imputation of Baseline LDL Cholesterol Concentration in Patients with Familial Hypercholesterolemia on Statins or Ezetimibe.

BACKGROUND: Familial hypercholesterolemia (FH) is the most frequent genetic disorder seen clinically and is characterized by increased LDL cholesterol (LDL-C) (>95th percentile), family history of increased LDL-C, premature atherosclerotic cardiovascular disease (ASCVD) in the patient or in first-degree relatives, presence of tendinous xanthomas or premature corneal arcus, or presence of a pathogenic mutation in the LDLR, PCSK9, or APOB genes. A diagnosis of FH has important clinical implications with respect to lifelong risk of ASCVD and requirement for intensive pharmacological therapy. The concentration of baseline LDL-C (untreated) is essential for the diagnosis of FH but is often not available because the individual is already on statin therapy. METHODS: To validate a new algorithm to impute baseline LDL-C, we examined 1297 patients. The baseline LDL-C was compared with the imputed baseline obtained within 18 months of the initiation of therapy. We compared the percent reduction in LDL-C on treatment from baseline with the published percent reductions. RESULTS: After eliminating individuals with missing data, nonstandard doses of statins, or medications other than statins or ezetimibe, we provide data on 951 patients. The mean ± SE baseline LDL-C was 243.0 (2.2) mg/dL [6.28 (0.06) mmol/L], and the mean ± SE imputed baseline LDL-C was 244.2 (2.6) mg/dL [6.31 (0.07) mmol/L] (P = 0.48). There was no difference in response according to the patient's sex or in percent reduction between observed and expected for individual doses or types of statin or ezetimibe. CONCLUSIONS: We provide a validated estimation of baseline LDL-C for patients with FH that may help clinicians in making a diagnosis.

Severe hyperhomocysteinemia due to cystathionine ß-synthase deficiency, and Factor V Leiden mutation in a patient with recurrent venous thrombosis.

Homocysteine is an amino acid that is toxic to vascular endothelial cells, and plasma elevations have been associated with venous thromboembolism. Severe hyperhomocysteinemia (>100 µmol/L) may result from mutations in the genes coding for enzymes in the trans-sulfuration or the folate/vitamin B12-dependent re-methylation pathways. Here, we report the case of a young woman with severe, recurrent thrombo-embolic events associated with severe hyperhomocysteinemia (111 µmol/L). We identified a homozygous mutation in the cystathionine ß -synthase gene (p.I278T) and the presence of the Factor V Leiden mutation. Family study shows segregation of elevated homocysteine in heterozygous relatives for the mutation in the cystathionine ß -synthase gene. Management consisted of anticoagulation with warfarin and supplementation with folate, vitamin B6 (pyridoxine) and vitamin B12. After twelve years of follow-up, plasma homocysteine levels remain in the moderate range (~20 µmol/L, reference range 8-12 µmol/L) and no further thromboembolic events were identified.

Lomitapide for treatment of homozygous familial hypercholesterolemia: The Québec experience.

BACKGROUND AND AIMS: Homozygous familial hypercholesterolemia (HoFH) is an orphan disease, most often caused by bi-allelic mutations of the LDLR gene. Patients with HoFH have elevated LDL-C levels >13 mmol/L, tendinous xanthomata and severe, premature atherosclerotic cardiovascular disease (ASCVD). Untreated, most HoFH patients die of ASCVD in youth. New therapeutic modalities include lomitapide, an inhibitor of microsomal triglyceride transfer protein that lowers hepatic LDL-C production. We have recently identified 79 Canadian patients with HoFH. Here, we describe our experience with lomitapide in the province of Quebec, a geographic area known to have a high prevalence of HoFH. METHODS: This is a retrospective case series of 12 HoFH patients followed at three lipidology centers in the province of Quebec. RESULTS: Mean age of the patients was 44 ± 18 years; age at time of HoFH diagnosis ranged from 2 to 59 years. All patients were on a statin and ezetimibe 10 mg/day and five patients were treated with LDL apheresis. Treatment with lomitapide reduced LDL-C levels by 38% (intention-to-treat). Intolerable gastrointestinal side effects were observed in 3/12 patients and were the main reason for treatment discontinuation. Three patients tolerated lomitapide at doses ranging between 5 and 30 mg/day without major side effects. Downwards drug titration was necessary in the 6 remaining patients because of gastrointestinal side effects (n = 5) and elevated liver enzymes (n = 1), and 2 of them finally discontinued treatment. CONCLUSIONS: Lomitapide may be used to further decrease LDL-C in HoFH patients; gastrointestinal side effects and hepatic toxicity may limit adherence.

Genetic testing for familial hypercholesterolemia: Impact on diagnosis, treatment and cardiovascular risk.

AIMS: Familial hypercholesterolemia (FH) is the most common genetic disorder in medicine, with a prevalence of 1/250. Affected individuals have elevated low-density lipoprotein cholesterol (LDL-C) and an increased lifetime risk of atherosclerotic cardiovascular disease (ASCVD). The diagnosis of FH is based on algorithms that include LDL-C levels, physical manifestations, family history of high LDL-C and premature ASCVD, and, more recently, genetic testing. We sought to determine the impact of genetic testing on the: 1) diagnosis of 'definite familial hypercholesterolemia', 2) initiation and adherence of lipid-lowering therapy and 3) risk of ASCVD. METHODS: We performed a systematic review and meta-analysis, pooling odds ratios and 95% confidence intervals for ASCVD from studies comparing risk estimates in individuals harboring FH-causing variants and unaffected individuals. RESULTS: After screening 3304 unique publications, 56 studies were included in the analysis. 1) Genetic testing provided confirmation of FH in 28-80%, over clinical criteria alone, depending on the diagnostic algorithm and the method of analysis. In two large population-based studies comprising 76,751 individuals, an FH-causing variant was identified in only 1.7-2.5% of subjects with an LDL-C > 4.9 mmol/L (190 mg/dL). 2) A confirmed molecular diagnosis increased lipid-lowering therapy adherence (five studies, n = 4181 definite FH). 3) Loss-of-function variant of the LDLR were at a markedly increased risk of myocardial infarction (odds ratio 6.77, 95% confidence interval 4.75-9.66), and patients with a milder (hypomorphic) pathogenic LDLR change had a 4.4-fold increase in risk (odds ratio 4.4, 95% confidence interval 2.34-8.26), compared with controls. CONCLUSION: DNA sequencing confirms the diagnosis of FH but has a poor yield in unselected patients whose sole criterion is an elevated LDL-C. Initiation and adherence to treatment is improved. The risk of ASCVD is 4.4- to 6.8-fold increased in patients with an FH-causing variant compared with controls, depending on the severity of the DNA change.

Prediction of Familial Hypercholesterolemia in Patients at High Atherosclerotic Cardiovascular Disease Risk Using a Recently Validated Algorithm.

BACKGROUND: The prevalence of heterozygous familial hypercholesterolemia (FH) is 1 of 250 in the general population and approximately 1 of 125 in patients with atherosclerotic cardiovascular disease (ASCVD), yet only a minority are diagnosed. The diagnostic criteria for FH rely on a point system using low-density lipoprotein cholesterol (LDL-C), family history, cutaneous manifestations, and molecular diagnosis. The aim of the present study was to determine the prevalence of FH in the Relating Evidence to Achieve Cholesterol Targets (REACT) registry. METHODS: Patients were enrolled as ASCVD (n = 86) or FH (n = 109) and with an LDL-C level > 3.0 mmol/L despite maximally tolerated statin therapy. FH was diagnosed clinically using a validated clinical application integrating an imputation for baseline (untreated) LDL-C levels. RESULTS: There were 109 men and 86 women with a mean age of 63 ± 12 years. Diabetes (29.7%), hypertension (62.1%), smoking (37.9%), and family history of premature ASCVD (59.5%) were common. On-treatment LDL-C was 4.26 ± 0.94 mmol/L. On the basis of the dose and type of statin ± ezetimibe, imputed baseline LDL-C was 7.04 ± 2.90 mmol/L. A diagnosis of probable/definite FH was found in 54.7%, 49.5%, and 61.5% of patients according to the Simon Broome, Dutch Lipid Clinic Network criteria, and the new Canadian FH definition, respectively. Of note, 40% of patients in the ASCVD inclusion subgroup had probable or definite FH. CONCLUSIONS: Our study reveals that a substantial proportion of patients with ASCVD whose LDL-C levels are > 3.0 mmol/L despite maximally tolerated statins have heterozygous FH. Clinicians should consider using the recently described algorithm to assess the possibility of FH in this high-risk population.

CONTEXTE: La prévalence de l'hypercholestérolémie familiale (HF) hétérozygote est de 1 cas sur 250 dans la population générale et d'environ 1 cas sur 125 chez les patients atteints d'une maladie cardiovasculaire athérosclérotique (MCVAS), pourtant on ne la diagnostique que dans une minorité de cas. Les critères diagnostiques de l'HF reposent sur un système de points utilisant comme paramètres le cholestérol à lipoprotéines de faible densité (C-LDL), les antécédents familiaux, les manifestations cutanées et le diagnostic moléculaire. La présente étude visait à déterminer la prévalence de l'HF parmi les patients répertoriés dans le registre REACT (Relating Evidence to Achieve Cholesterol Targets). MÉTHODOLOGIE: Les patients admis à l'étude étaient considérés comme étant atteints d'une MCVAS (n = 86) ou d'une HF (n = 109) et présentaient un taux de C-LDL > 3,0 mmol/l malgré la prise d'un traitement par statine à la dose maximale tolérée. L'HF a été diagnostiquée sur le plan clinique à l'aide d'une application clinique validée incluant une imputation des taux de C-LDL initiaux (en l'absence de traitement). RÉSULTATS: L'étude comptait 86 femmes et 109 hommes âgés en moyenne de 63 ± 12 ans. Le diabète (29,7 %), l'hypertension (62,1 %), le tabagisme (37,9 %) et les antécédents familiaux de MCVAS prématurée (59,5 %) étaient fréquents. Sous traitement, le taux de C-LDL était de 4,26 ± 0,94 mmol/l. D'après la dose et le type de statine ± ézétimibe administrés, le taux de C-LDL imputé au départ était de 7,04 ± 2,90 mmol/l. Un diagnostic d'HF probable ou certaine a été établi respectivement chez 54,7 %, 49,5 % et 61,5 % des patients selon les critères de Simon Broome et du Dutch Lipid Clinic Network, ainsi que la nouvelle définition canadienne de l'HF. Notons que 40 % des patients dans le sous-groupe d'inclusion de la MCVAS présentaient une HF probable ou certaine. CONCLUSIONS: Notre étude révèle qu'une proportion importante de patients atteints de MCVAS dont les taux de C-LDL sont > 3,0 mmol/l malgré la prise de statines à la dose maximale tolérée présentent une HF hétérozygote. Les cliniciens devraient envisager d'utiliser l'algorithme récemment décrit pour évaluer la présence possible d'une HF dans cette population à haut risque.

Severe xanthomatosis in heterozygous familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia is a genetic lipoprotein disorder characterized by elevated plasma low-density lipoprotein cholesterol level, (tendinous xanthomas, xanthelasmas, and premature arcus corneus) and early onset atherosclerotic cardiovascular disease. Familial hypercholesterolemia is caused by mutations in the low-density lipoprotein receptor, apolipoprotein B or proprotein convertase subtilisin/kexin type 9 genes. Rare mutations in low-density lipoprotein receptor adapter protein 1, APOE p.Leu167del or lysosomal acid lipase genes can mimic FH. The prevalence of heterozygous familial hypercholesterolemia is estimated to be 1/250 worldwide, although some populations with founder effects show a higher prevalence. The rare homozygous form has an estimated prevalence of 0.000004 or 1/250,000 and is characterized by markedly elevated low-density lipoprotein cholesterol, skin manifestations (planar xanthomas, tendinous xanthomas) in childhood and extremely premature atherosclerotic cardiovascular disease. While tendinous xanthomas are considered pathognomonic for familial hypercholesterolemia, they can also be found in rare diseases, including sitosterolemia. Here, we report a case of severe tendinous xanthomatosis with heterozygous familial hypercholesterolemia due to the low-density lipoprotein receptor del >15 kb mutation. The phenotypic expression of the disease is out of proportion with the genetic diagnosis or biochemical measurements. CASE REPORT: We report the case of 51-year-old woman of French-Canadian origin diagnosed with heterozygous familial hypercholesterolemia since age 12. She presented with hypercholesterolemia with total cholesterol 7.6 mmol/L, with an imputed low-density lipoprotein cholesterol level of 6.5 mmol/L. She had extensive tendinous xanthomas of the Achilles tendons, knees, elbows and metacarpophalangeal joints. Because of cosmetic disfigurement, she had multiple excisions of Achilles, knee and elbow xanthomas, albeit with rapid recurrence. Our patient has a significant family history of lung cancer and other autoimmune diseases associated with familial hypercholesterolemia and xanthoma. Lipid-lowering therapy was started, at age 12; which included initially cholestyramine, then changed to statin and ezetimibe. Eventually, evolocumab was added. Despite trying different lipid-lowering therapy, there has been no noticeable decrease in the size of the xanthomas. CONCLUSION: Our patient has severe xanthomatosis out of proportion with the genetic diagnosis or biochemical measurements. Her xanthomatosis did not improve by pharmacological therapy consisting of statins and evolocumab despite a 50% reduction in low-density lipoprotein cholesterol. It is likely that the patient presented here has a second genetic disorder that leads to extensive xanthomatosis.

Simplified Canadian Definition for Familial Hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal codominant lipoprotein disorder characterized by elevated low-density lipoprotein cholesterol (LDL-C) and high risk of premature atherosclerotic cardiovascular disease. Definitions for FH rely on complex algorithms that are on the basis of levels of total or LDL-C, clinical features, family history, and DNA analysis that are often difficult to obtain. We propose a novel simplified definition for FH. Definite FH includes: (1) elevated LDL-C (≥ 8.50 mmol/L); or (2) LDL-C ≥ 5.0 mmol/L (for age 40 years or older; ≥ 4.0 mmol/L if age younger than 18 years; and ≥ 4.5 mmol/L if age is between 18 and 39 years) when associated with at least 1 of: (1) tendon xanthomas; or (2) causal DNA mutation in the LDLR, APOB, or PCSK9 genes in the proband or first-degree relative. Probable FH is defined as subjects with an elevated LDL-C (≥ 5.0 mmol/L) and the presence of premature atherosclerotic cardiovascular disease in the patient or a first-degree relative or an elevated LDL-C in a first-degree relative. LDL-C cut points were determined from a large database comprising > 3.3 million subjects. To compare the proposed definition with currently used algorithms (ie, the Simon Broome Register and Dutch Lipid Clinic Network), we performed concordance analyses in 5987 individuals from Canada. The new FH definition showed very good agreement compared with the Simon Broome Register and Dutch Lipid Clinic Network criteria (κ = 0.969 and 0.966, respectively). In conclusion, the proposed FH definition has diagnostic performance comparable to existing criteria, but adapted to the Canadian population, and will facilitate the diagnosis of FH patients.

Canadian Cardiovascular Society Position Statement on Familial Hypercholesterolemia: Update 2018.

Familial hypercholesterolemia (FH) is the most common monogenic disorder causing premature atherosclerotic cardiovascular disease. It affects 1 in 250 individuals worldwide, and of the approximately 145,000 Canadians estimated to have FH, most are undiagnosed. Herein, we provide an update of the 2014 Canadian Cardiovascular Society position statement on FH addressing the need for case identification, prompt recognition, and treatment with statins and ezetimibe, and cascade family screening. We provide a new Canadian definition for FH and tools for clinicians to make a diagnosis. The risk of atherosclerotic cardiovascular disease in patients with "definite" FH is 10- to 20-fold that of a normolipidemic individual and initiating treatment in youth or young adulthood can normalize life expectancy. Target levels for low-density lipoprotein cholesterol are proposed and are aligned with the Canadian Cardiovascular Society guidelines on dyslipidemia. Recommendation for the use of inhibitors of proprotein convertase kexin/subtilisin type 9 are made in patients who cannot achieve therapeutic low-density lipoprotein cholesterol targets on maximally tolerated statins and ezetimibe. The writing committee used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology in the preparation of the present document, which offers guidance for practical evaluation and management of patients with FH. This position statement also aims to raise awareness of FH nationally, and to mobilize patient support, promote knowledge translation, and availability of treatment and health care resources for this under-recognized, but important medical condition.

Estrogen-associated severe hypertriglyceridemia with pancreatitis.

BACKGROUND: Estrogen, whether therapeutic or physiologic, can cause hypertriglyceridemia. Hypertriglyceridemia-induced pancreatitis is a rare complication. CASES: We report 2 women who developed estrogen-associated severe hypertriglyceridemia with pancreatitis. The first patient developed pancreatitis secondary to hypertriglyceridemia associated with in vitro fertilization cycles. Marked reduction in her triglyceride was achieved with dietary restrictions and fibrate. The second patient developed pancreatitis secondary to hypertriglyceridemia during her pregnancies. She was noncompliant with the treatment; therefore, her triglyceride remained high after delivery. In both patients, no hypertriglyceridemia-associated genes mutations were identified, although the second patient had strong polygenic susceptibility to hypertriglyceridemia. CONCLUSION: Estrogen-induced severe hypertriglyceridemia with pancreatitis can be a life-threatening condition. Screening in high-risk patients is crucial to prevent subsequent complications.

Aortic Calcification Progression in Heterozygote Familial Hypercholesterolemia.

BACKGROUND: Patients with homozygous and heterozygous familial hypercholesterolemia (HeFH) develop severe aortic calcifications in an age- and gene dosage-dependent manner. The purpose of this study was to determine the rate of progression of aortic calcification in patients with HeFH. METHODS: We performed thoracoabdominal computed tomography scans and quantified aortic calcium (AoCa) score in 16 HeFH patients, all with the null low-density lipoprotein (LDL) receptor DEL15Kb mutation. Patients (12 men, 4 women) were rescanned an average of 8.2 ± 0.8 years after the first scan. RESULTS: Mean LDL cholesterol (LDL-C) during treatment was 2.53 mmol/L; all patients were receiving high-dose statin/ezetimibe; 5 of 16 were receiving evolocumab. Baseline LDL-C was 7.6 ± 1.3 mmol/L. Aortic calcifications increased in all patients in an exponential fashion with respect to age. Age was the strongest correlate of AoCa score. Cholesterol, LDL-C, or age × cholesterol did not correlate with AoCa score or its progression. Control patients (n = 31; 8 male, 23 female; mean age 61 ± 11 years) who underwent virtual colonoscopy were rescanned over the same period and showed an abdominal AoCa score of 1472 ± 2489 compared with 7916 ± 7060 Agatston U (P < 0.001) in patients with HeFH during treatment (mean age, 60 ± 14 years). The rate of progression was 159 vs 312 Agatston U/y in control participants vs those with HeFH. CONCLUSIONS: HeFH patients exhibit accelerated aortic calcification that increases exponentially with age. LDL-C at baseline or during treatment seems to have little effect on the rate of progression of AoCa score. Strategies to prevent aortic calcifications with statins have not met with clinical success and novel approaches are required; statins might also contribute to the process of arterial calcification.