Zahid Ahmad

Low prevalence of mutations in known loci for autosomal dominant hypercholesterolemia in a multiethnic patient cohort

Background—Autosomal dominant hypercholesterolemia (ADH), characterized by elevated plasma levels of low-density lipoprotein (LDL)-cholesterol, is caused by variants in at least 3 different genes: LDL receptor (LDLR), apolipoprotein B-100, and proprotein convertase subtilisin-like kexin type 9. There is paucity of data about the molecular basis of ADH among ethnic groups other than those of European or Japanese descent. Here, we examined the molecular basis of ADH in a multiethnic patient cohort from lipid clinics in a large, urban US city. Methods and Results—A total of 38 men and 53 women, aged 22 to 76 years, met modified Simon-Broome criteria for ADH and were screened for mutations in the exons and consensus splice sites of LDLR, and in selected exons of apolipoprotein B-100 and proprotein convertase subtilisin-like kexin type 9. Deletions and duplications of LDLR exons were detected with multiplex ligation-dependent probe amplification. Heterozygous variants in LDLR were identified in 30 patients and in apolipoprotein B-100 in 1 patient. The remaining 60 patients (65%) had unexplained ADH. A higher proportion of blacks (77%) than either non-Hispanic whites (57%) or Hispanics (53%) had unexplained ADH. Compared with patients with LDLR variants, those with unexplained ADH had lower levels of LDL-cholesterol (292±47 mg/dL versus 239±42 mg/dL, respectively; P<0.0001) and higher levels of high-density lipoprotein cholesterol (45±12 mg/dL versus 54±13 mg/dL, respectively; P=0.003). Conclusions—Our findings suggest that additional loci may contribute to ADH, especially in understudied populations such as blacks.

Treatment Gaps in Adults with Heterozygous Familial Hypercholesterolemia in the United States: Data from the CASCADE-FH Registry

Background— Cardiovascular disease burden and treatment patterns among patients with familial hypercholesterolemia (FH) in the United States remain poorly described. In 2013, the FH Foundation launched the Cascade Screening for Awareness and Detection (CASCADE) of FH Registry to address this knowledge gap. Methods and Results— We conducted a cross-sectional analysis of 1295 adults with heterozygous FH enrolled in the CASCADE-FH Registry from 11 US lipid clinics. Median age at initiation of lipid-lowering therapy was 39 years, and median age at FH diagnosis was 47 years. Prevalent coronary heart disease was reported in 36% of patients, and 61% exhibited 1 or more modifiable risk factors. Median untreated low-density lipoprotein cholesterol (LDL-C) was 239 mg/dL. At enrollment, median LDL-C was 141 mg/dL; 42% of patients were taking high-intensity statin therapy and 45% received >1 LDL-lowering medication. Among FH patients receiving LDL-lowering medication(s), 25% achieved an LDL-C <100 mg/dL and 41% achieved a ≥50% LDL-C reduction. Factors associated with prevalent coronary heart disease included diabetes mellitus (adjusted odds ratio 1.74; 95% confidence interval 1.08–2.82) and hypertension (2.48; 1.92–3.21). Factors associated with a ≥50% LDL-C reduction from untreated levels included high-intensity statin use (7.33; 1.86–28.86) and use of >1 LDL-lowering medication (1.80; 1.34–2.41). Conclusions— FH patients in the CASCADE-FH Registry are diagnosed late in life and often do not achieve adequate LDL-C lowering, despite a high prevalence of coronary heart disease and risk factors. These findings highlight the need for earlier diagnosis of FH and initiation of lipid-lowering therapy, more consistent use of guideline-recommended LDL-lowering therapy, and comprehensive management of traditional coronary heart disease risk factors.

Early onset mandibuloacral dysplasia due to compound heterozygous mutations in ZMPSTE24

Mandibuloacral dysplasia (MAD) is an autosomal recessive disorder characterized by hypoplasia of the mandible and clavicles, acro‐osteolysis, and lipodystrophy due to mutations in LMNA or ZMPSTE24. Only six MAD patients are reported so far with ZMPSTE24 mutations and limited phenotypic data are available for them. Here, we report on two brothers (4 years and 9‐month old) with early onset MAD due to ZMPSTE24 mutations in whom thin skin was noted as early as 5 months of age. Both had micrognathia, mottled hyperpigmentation, and enlarged fontanelles but little evidence of lipodystrophy. There was no delay of mental development. The older brother had small pinched nose, short clavicles, acro‐osteolysis, stunted growth, joint stiffness, and repeated fractures. There was no evidence of renal disease. Both patients were compound heterozygotes harboring a previously reported missense ZMPSTE24 mutation, p.Pro248Leu, and a novel null mutation, p.Trp450stop. These patients and the review of literature reveal that compared to MAD patients with LMNA mutations, those with ZMPSTE24 mutations develop manifestations earlier in life. Other distinguishing features in MAD due to ZMPSTE24 mutations may include premature birth, renal disease, calcified skin nodules, and lack of acanthosis nigricans. We conclude that in patients with MAD due to ZMPSTE24 mutations, the onset of disease manifestations such as thin skin and micrognathia occurs as early as 5 months of age. In these patients, skeletal phenotype presents earlier whereas lipodystrophy and renal disease may occur later in life.

Genotype-phenotype relationships in patients with type I hyperlipoproteinemia

CONTEXT Type I hyperlipoproteinemia (T1HLP) is a rare, autosomal recessive disorder characterized by extreme hypertriglyceridemia that fails to respond to lipid-lowering agents, predisposing to frequent attacks of acute pancreatitis. Mutations in lipoprotein lipase (LPL), apolipoprotein CII (APOC2), lipase maturation factor 1 (LMF1), glycosyl-phosphatidylinositol anchored high-density lipoprotein-binding protein 1 (GPIHBP1), and apolipoprotein AV (APOA5) cause T1HLP, but we lack data on phenotypic variations among the different genetic subtypes. OBJECTIVE To study genotype-phenotype relationships among subtypes of T1HLP patients. DESIGN/INTERVENTION Genetic screening for mutations in LPL, APOC2, GPIHBP1, LMF1, and APOA5. SETTING Tertiary referral center. PATIENTS Ten patients (7 female, 3 male) with chylomicronemia, serum triglyceride levels about 2000 mg/dL, and no secondary causes of hypertriglyceridemia. MAIN OUTCOME MEASURES Genotyping and phenotypic features. RESULTS Four patients harbored homozygous or compound heterozygous mutations in LPL, 3 had homozygous mutations in GPIHBP1, and 1 had a heterozygous APOA5 mutation. We failed to fully identify the genetic etiology in 2 cases: 1 had a heterozygous LPL mutation only and another did not have any mutations. We identified 2 interesting phenotypic features: the patient with heterozygous APOA5 mutation normalized triglyceride levels with weight loss and fish oil therapy, and all 7 female patients were anemic. CONCLUSIONS Our data suggest the possibility of novel loci for T1HLP. We observed that heterozygous APOA5 mutation can cause T1HLP but such patients may unexpectedly respond to therapy, and females with T1HLP suffer from anemia. Further studies of larger cohorts may elucidate more phenotype-genotypes relationships among T1HLP subtypes.

Mediastinal paragangliomas: association with mutations in the succinate dehydrogenase genes and aggressive behavior

Extra-adrenal pheochromocytomas, otherwise known as paragangliomas (PGLs), account for about 20% of catecholamine-producing tumors. Catecholamine excess and mutations in the genes encoding succinate dehydrogenase subunits (SDHx) are frequently found in patients with PGLs. Only 2% of PGLs are found in the mediastinum, and little is known about genetic alterations in patients with mediastinal PGLs, catecholamine production by these tumors, or their clinical behavior. We hypothesized that most mediastinal PGLs are associated with germ line SDHx mutations, norepinephrine and/or dopamine excess, and aggressive behavior. The objective of this study was to characterize genetic, biochemical, and clinical data in a series of ten patients with mediastinal PGLs. All ten primary mediastinal PGL patients had germ line SDHx mutations, six in SDHB, and four in SDHD genes. Chest or back pain were the most common presenting symptoms (five patients), and catecholamines and/or their metabolites were elevated in seven patients. Additional tumors included head and neck PGLs in four patients, pheochromocytoma in one patient, and bladder PGL in another. Metastatic disease was documented in six patients (60%), and a concurrent abdominal mass was found in one patient. We conclude that mediastinal PGLs are strongly associated with SDHB and SDHD gene mutations, noradrenergic phenotype, and aggressive behavior. The present data suggest that all patients with mediastinal PGLs should be screened for SDHx gene mutations, regardless of age.

ANGPTL3 Inhibition in Homozygous Familial Hypercholesterolemia

Evinacumab, a monoclonal antibody that blocks ANGPTL3, was administered to nine adults with homozygous familial hypercholesterolemia. At 4 weeks, LDL cholesterol was reduced by a mean of 49%, with a mean absolute change from baseline of −157 mg per deciliter.

Familial chylomicronemia syndrome and response to medium-chain triglyceride therapy in an infant with novel mutations in GPIHBP1

BACKGROUND Severe hypertriglyceridemia predisposes to attacks of acute pancreatitis, a serious condition complicated by multiorgan failure, pancreatic necrosis, and mortality rates up to 20% in adults and 6.5% in children. OVERVIEW We describe an infant who suffered from an episode of acute pancreatitis from severe hypertriglyceridemia. Two major challenges complicate the case: identifying the etiology of severe hypertriglyceridemia and finding an efficacious treatment. A thorough history, physical examination, and laboratory workup failed to identify a clear etiology, prompting a genetic workup that identified compound heterozygous mutations in the glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) gene. This patients hypertriglyceridemia responded to an infant formula rich in medium chain triglycerides (MCTs), and she remained free of pancreatitis 6 months later. CONCLUSIONS This case highlights the need to pursue a genetic evaluation in the absence of secondary causes of severe hypertriglyceridemia in infants. Patients with mutations in GPIHBP1 fail to respond to currently available lipid-lowering agents so dietary management-specifically, an extremely low-fat diet and supplementation with MCT-remains the cornerstone of therapy. Treatment in infants should focus on dietary measures rather than pharmacologic agents.

Effect of PCSK9 inhibitors on clinical outcomes in patients with hypercholesterolemia: A meta-analysis of 35 randomized controlled trials

Background We sought to examine the efficacy and safety of 2 PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors: alirocumab and evolocumab. Methods and Results We performed a systematic review and meta‐analysis of randomized controlled trials comparing treatment with and without PCSK9 inhibitors; 35 randomized controlled trials comprising 45 539 patients (mean follow‐up: 85.5 weeks) were included. Mean age was 61.0±2.8 years, and mean baseline low‐density lipoprotein cholesterol was 106±22 mg/dL. Compared with no PCSK9 inhibitor therapy, treatment with a PCSK9 inhibitor was associated with a lower rate of myocardial infarction (2.3% versus 3.6%; odds ratio [OR]: 0.72 [95% confidence interval (CI), 0.64–0.81]; P<0.001), stroke (1.0% versus 1.4%; OR: 0.80 [95% CI, 0.67–0.96]; P=0.02), and coronary revascularization (4.2% versus 5.8%; OR: 0.78 [95% CI, 0.71–0.86]; P<0.001). Overall, no significant change was observed in all‐cause mortality (OR: 0.71 [95% CI, 0.47–1.09]; P=0.12) or cardiovascular mortality (OR: 1.01 [95% CI, 0.85–1.19]; P=0.95). A significant association was observed between higher baseline low‐density lipoprotein cholesterol and benefit in all‐cause mortality (P=0.038). No significant change was observed in neurocognitive adverse events (OR: 1.12 [95% CI, 0.88–1.42]; P=0.37), myalgia (OR: 0.95 [95% CI, 0.75–1.20]; P=0.65), new onset or worsening of preexisting diabetes mellitus (OR: 1.05 [95% CI, 0.95–1.17]; P=0.32), and increase in levels of creatine kinase (OR: 0.84 [95% CI, 0.70–1.01]; P=0.06) or alanine or aspartate aminotransferase (OR: 0.96 [95% CI, 0.82–1.12]; P=0.61). Conclusions Treatment with a PCSK9 inhibitor is well tolerated and improves cardiovascular outcomes. Although no overall benefit was noted in all‐cause or cardiovascular mortality, such benefit may be achievable in patients with higher baseline low‐density lipoprotein cholesterol.

The burden of familial chylomicronemia syndrome: interim results from the IN-FOCUS study

ABSTRACT Background: Familial Chylomicronemia Syndrome (FCS) is a rare genetic disorder that is caused by a decrease or an absence of lipoprotein lipase activity. FCS is characterized by marked accumulation of chylomicrons and extreme hypertriglyceridemia, which have major effects on both physical and mental health. To date, there have been no systematic efforts to characterize the impact of chylomicronemia on FCS patients’ lives. In particular, the impact of FCS on the burden of illness (BoI) and quality of life (QoL) has not been fully described in the literature. Methods: IN-FOCUS was a comprehensive web-based research survey of patients with FCS focused on capturing the BoI and impact on QoL associated with FCS. Sixty patients from the US diagnosed with FCS participated. Patients described multiple symptoms spanning across physical, emotional and cognitive domains. Results: Patients on average cycled through 5 physicians of varying specialty before being diagnosed with FCS, reflecting a lengthy journey to diagnosis Nearly all respondents indicated that FCS had a major impact on BoI and QoL and significantly influenced their career choice and employment status, and caused significant work loss due to their disease. Conclusion: FCS imparts a considerable burden across multiple domains with reported impairment on activities of daily living and QoL.

Stock market development and economic growth: A comparative study of Pakistan and Bangladesh

This paper examined the relationship between stock market development and economic growth of two Asian developing countries, that is, Pakistan and Bangladesh, after the liberalization period of 1990s. The relationship measured were in terms of size (market capitalization), liquidity (total value of stocks traded and stock turnover ratio) and volume (total number of companies listed in the stock exchange of each of the country). The study of comparative analysis was done with the help of tables and charts. The econometric results of the study by employing the regression analysis showed that Pakistan stock markets contribute to the economic growth in terms of the large size of its stock market whereas Bangladesh stock market contributes to the economic growth in terms of the liquidity of its stock market. Bangladesh economic growth was found to be comparatively better than economic growth of Pakistan. The study revealed that the stock markets in Pakistan and Bangladesh do not play a major role in the economic growth but rather, these financial institutions are the driving forces for the economic growth of the country.