Long-chain 3-hydroxyacyl Coenzyme Research Articles

A proposal for an updated staging system for LCHADD retinopathy

ABSTRACT Objective To develop an updated staging system for long-chain 3-hydroxyacyl coenzyme A dehydrogenase deficiency (LCHADD) chorioretinopathy based on contemporary multimodal imaging and electrophysiology. Methods We evaluated forty cases of patients with genetically confirmed LCHADD or trifunctional protein deficiency (TFPD) enrolled in a prospective natural history study. Wide-field fundus photographs, fundus autofluorescence (FAF), optical coherence tomography (OCT), and full-field electroretinogram (ffERG) were reviewed and graded for severity. Results Two independent experts first graded fundus photos and electrophysiology to classify the stage of chorioretinopathy based upon an existing published system. With newer imaging modalities and improved electrophysiology, many patients did not fit cleanly into a single traditional staging group. Therefore, we developed a novel staging system that better delineated the progression of LCHADD retinopathy. We maintained the four previous delineated stages but created substages A and B in stages 2 to 3 to achieve better differentiation. Discussion Previous staging systems of LCHADD chorioretinopathy relied on only on the assessment of standard 30 to 45-degree fundus photographs, visual acuity, fluorescein angiography (FA), and ffERG. Advances in recordings of ffERG and multimodal imaging with wider fields of view, allow better assessment of retinal changes. Following these advanced assessments, seven patients did not fit neatly into the original classification system and were therefore recategorized under the new proposed system. Conclusion The new proposed staging system improves the classification of LCHADD chorioretinopathy, with the potential to lead to a deeper understanding of the disease’s progression and serve as a more reliable reference point for future therapeutic research.

Clinical Characteristics and Sequelae of Severe Hypertriglyceridemia in Pediatrics

Severe hypertriglyceridemia (HTG) (i.e., plasma triglycerides [TGs] >1,000 mg/dL) in children is a rare but pernicious and understudied condition. Our objective was to evaluate the etiology, characteristics, and sequelae of severe pediatric HTG. This was a retrospective electronic medical record review of pediatric patients with severe HTG at a tertiary referral Children's hospital over a 17-year period. There were a total of 124 patients with severe HTG. The etiology varied: hemato-oncologic (n = 48), diabetes and insulin resistance-related (n = 46), total parenteral nutrition (TPN)-related (n = 6), renal (n = 12), and miscellaneous (n = 12). There was considerable variability in the number of days for the plasma TGs to decrease to <1,000 mg/dL (147.7 ± 567.3 days) and to further decrease to <500 mg/dL (136.84 ± 230.9 days). Patients with diabetes required the longest time to improve their plasma TGs (165.8 ± 305.7 days) compared to other groups. There were 11 cases of pancreatitis, comorbid with diabetes (n = 5), hemato-oncologic conditions (n = 3), and TPN (n = 3). Sixty-seven patients (54%) had persistent HTG. Severe HTG in pediatrics is commonly due to secondary causes. Patients with diabetes tend to have a longer course of dyslipidemia. A substantial number of patients had persistent dyslipidemia, indicating underlying genetic susceptibility to HTG that is phenotypically expressed consequent to a secondary metabolic insult. DKA = diabetic ketoacidosis; EMR = electronic medical record; GSD = glycogen storage disorder; HbA1c = hemoglobin A1c; HIV = human immunodeficiency virus; HTG = hypertriglyceridemia; ICD-9 = International Classification of Diseases-Ninth Revision; IV = intravenous; LCHAD = long-chain 3-hydroxyacyl coenzyme A dehydrogenase deficiency; LPL = lipoprotein lipase; NPO = nothing by mouth; PCOS = polycystic ovary syndrome; T1DM = type 1 diabetes mellitus; T2DM = type 2 diabetes mellitus; TG = triglyceride; TPN = total parenteral nutrition; VLDL = very-low-density lipoprotein.

Mutations in Long-Chain 3-Hydroxyacyl Coenzyme a Dehydrogenase are Associated with Placental Maternal Floor Infarction/Massive Perivillous Fibrin Deposition

Maternal floor infarction/massive perivillous fibrin deposition (MFI/MPVFD) of the placenta has an unclear etiology. The placenta of an 8-month-old child diagnosed with long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) deficiency reportedly showed MFI, but no further evidence of a direct association between MFI/MPVFD and LCHAD deficiency has been documented. Three cases of MFI/MPVFD were studied. Paraffin blocks of placental tissue were retrieved, tissue scrolls were harvested, and DNA was extracted. The alpha-subunit of the mitochondrial trifunctional protein containing the LCHAD coding region (HADHA) was subsequently amplified using specific primer sets and directly sequenced by the dideoxy chain termination method. All 3 placentas demonstrated heterozygous mutations in the HADHA gene. A sample from a 25-4/7 week gestation growth-restricted female infant revealed a heterozygous mutation in exon 11, 1072C>A (glutamine to lysine, Qln358Lys) with a heterozygous sequence difference in the intron following exon 6 (insertion of a T at position +9, +9insT). The 2nd sample from a 32-4/7 week gestation stillborn fetus revealed a heterozygous mutation (+3A>G after exon 3) and a clear homozygous sequence difference in exon 17. The 3rd sample from a 31 weeks gestation infant revealed heterozygosity for the+3A>G mutation after exon 3. All 3 placentas with MFI/MPVFD demonstrated heterozygous mutations in the HADHA gene, and 2 of the 3 placentas had 2 DNA changes. Given a background incidence of heterozygosity for LCHAD mutations of approximately 1 in 220, these findings lend support to the hypothesis that LCHAD mutations may be directly associated with and potentially causative of MFI/MPVFD.

Refined Staging for Chorioretinopathy in Long-Chain 3-Hydroxyacyl Coenzyme A Dehydrogenase Deficiency

Objective: Neonatal screening and earlier diagnosis have improved the prognosis of long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) deficiency, which causes a need to refine the staging of the pigmentary chorioretinopathy and thus improve monitoring and comparability of patients under dietary therapy. Methods: Seven children with LCHAD deficiency caused by homozygous G1528C mutation attended sequential fundus photography for stage 2 chorioretinopathy in 1997–2006. After arranging 21 pairs of fundus photographs according to the severity of the fundus changes, the images best representing 3 different grades of pigmentary deposits (P1–P3) and retinal pigment epithelial (RPE) atrophy (A1–A3) were chosen as reference photographs. To evaluate the substaging, 29 pairs of photographs were graded according to the reference photographs. Results: In the assessment of pigmentary deposits, the 3 ophthalmologists agreed in 41% and differed by a single substage in 45% of instances (combined weighted ĸ statistic was 0.38, indicating moderate agreement). In pairwise comparisons, the weighted ĸ statistic ranged from 0.31 to 0.56 (agreement, 71–81%). In the assessment of RPE atrophy, all 3 raters agreed in 17% and 2 raters in 70% of instances (combined ĸ statistic 0.018, indicating poor agreement). Discussion: Despite variation in imaging techniques and limitations in the visual assessment of fundus photographs, the agreement obtained in grading the pigmentary deposits was comparable to that reported for photographic grading of retinopathy of prematurity. We recommend photographic documentation and substaging based on reference photographs in the follow-up of LCHAD retinopathy. The refined staging allows a more detailed assessment on the progression of the retinopathy and optimization of the therapeutic protocols in individual patients and between centres using different therapeutic protocols.

Liver diseases unique to pregnancy: A 2010 update

Liver disorders occurring during pregnancy may be specifically pregnancy-related, or may be due to an intercurrent or chronic liver disease, which may present in anyone, pregnant or not. This review focuses on the liver diseases unique to pregnancy. Hyperemesis gravidarum, which occurs during early pregnancy, may be associated with liver dysfunction. Intrahepatic cholestasis of pregnancy typically occurs during the second or third trimester. Pruritus and the associated biological signs of cholestasis improve rapidly after delivery. Mutations in gene encoding biliary transporters, especially ABCB4 encoding the multidrug resistance 3 protein, have been found to be associated with this complex disease. Ursodeoxycholic acid is currently the most effective medical treatment in improving pruritus and liver tests. Pre-eclampsia, which presents in late pregnancy frequently involves the liver, and HELLP syndrome (Hemolysis-Elevated Liver enzymes-Low Platelets) is a life-threatening complication. Prognosis of acute fatty liver of pregnancy has been radically transformed by early delivery, and clinicians must have a high index of suspicion for this condition when a woman presents nausea or vomiting, epigastric pain, jaundice, or polyuria-polydipsia during the third trimester. Acute fatty liver of pregnancy has been found to be associated with a defect of long-chain 3-hydroxyacyl coenzyme A dehydrogenase in the fetus, and mothers and their offspring should undergo DNA testing at least for the main associated genetic mutation (c.1528G>C).

Highly Active Antiretroviral Therapy Does Not Affect Mitochondrial β-Oxidation of Fatty Acids: An in Vitro Study in Fibroblasts

Preeclampsia is a multifactorial pregnancy-specific disease. In some cases, severe preeclampsia and related disorders of acute fatty liver of pregnancy and hemolysis, elevated liver enzymes, low platelets syndrome are associated with inherited defects in mitochondrial beta-oxidation of fatty acids, especially a deficiency of long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD). Recently, an unexplained increase in the incidence of preeclampsia has been documented in human immunodeficiency virus (HIV)-infected pregnant women on treatment with highly active antiretroviral therapy (HAART). We performed this study to determine if antiretroviral drugs affect mitochondrial beta-oxidation fatty acids in vitro. Two normal and 1 heterozygous LCHAD-deficient cell lines were exposed to up to 5 times the therapeutic concentrations of the following antiretroviral drugs: nevirapine, didanosine, lamivudine, and a combination of nelfinavir, zidovudine, and lamivudine. One homozygous LCHAD-deficient cell line served as the positive control. After exposure of the fibroblasts to these drugs for periods ranging from 2 to 10 days, accumulations of even-chain 3-hydroxy fatty acids (3-OH-C6 to 3-OH-C18) in the culture media were measured by stable-isotope dilution gas chromatography/mass spectrometry. Compared to the respective unexposed fibroblasts, there was no significant build-up of 3-hydroxy fatty acids in the culture media of normal or heterozygous LCHAD-deficient fibroblasts exposed to antiretroviral drugs. Our results show that the commonly used antiretroviral drugs do not adversely affect fatty acid oxidation in fibroblasts. Therefore, an altered fatty acid oxidation may not be the mechanism for the reported increased risk of preeclampsia in HIV-infected pregnant women on HAART.

Identification of novel mutations of the HADHA and HADHB genes in patients with mitochondrial trifunctional protein deficiency

Patients with long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) deficiency manifest hypoketotic hypoglycemia, hepatomegaly, hypotonia, lactic acidemia, acute renal failure, cardiomyopathy, and sudden death. We describe four novel mutations of the alpha- and beta-subunits of the mitochondrial trifunctional protein in four patients from three unrelated families. Their plasma acylcarnitine profiles suggested the presence of LCHAD deficiency by demonstrating highly elevated 3-hydroxyacyl carnitines by tandem mass spectrometry (MS/MS). Patients 1 and 2 had siblings who had died of lactic acidemia during the neonatal period. These patients also manifested lactic acidemia and died in the neonatal period. Patient 3 had a family history of Reye-like syndrome. She exhibited acute renal failure, rhabdomyolysis, pericardial effusion, and myopathy at the age of 12 years. DNA analysis of patients 1 and 2 revealed homozygosity for a c.1689+2T>G mutation of the HADHA gene, resulting in the skipping of exon 16 with an in-frame 69-bp deletion. Patient 3 was a compound heterozygosity of the HADHB gene, N307D/N389D. Patient 4, a 25-month-old baby, manifested recurrent episodes of lethargy, metabolic acidosis, elevated liver enzymes, and dark urine from the age of 10 months. Mutation analysis of the HADHB gene of patient 4 identified compound heterozygosity of N114D/N307D.

Maternal heterozygosity for a mitochondrial trifunctional protein mutation as a cause for liver disease in pregnancy

Acute fatty liver of pregnancy (AFLP) and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome are serious complications of pregnancy associated with significant maternal and perinatal morbidity and mortality. In previous reports, we have documented an association between AFLP and fetal deficiency of long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) [N. Engl. J. Med. 340 (1999) 1723-1731; JAMA 288 (2002) 2163-2166]. LCHAD activity resides in the alpha-subunit of the mitochondrial trifunctional protein (MTP), a complex protein that catalyzes beta-oxidation of long chain fatty acids. In all reported cases, the fetus carried a common alpha-subunit MTP mutation (G1528C, E474Q) on one or both alleles. However, the association between fetal LCHAD deficiency and the maternal HELLP syndrome has been limited. Here, we report a case history of a 27-year-old black female who underwent Cesarean section for placenta previa and fetal distress at 36 weeks gestation. The newborn was a healthy male child. Post-delivery, the mother developed severe HELLP syndrome with complications resulting in death of the patient. We used single strand conformation variance and nucleotide sequence analyses to screen DNA isolated from the mother and the newborn for mutations in the MTP alpha-subunit. The mother was heterozygous for a novel mutation (C1072A, Q322K) in exon 11 of the LCHAD domain of the MTP, while the fetal genotype was completely normal. We hypothesize that, in some cases, maternal heterozygosity for an MTP mutation maybe sufficient to cause the development of maternal liver disease without carrying an affected fetus. Combination of the metabolic stress of pregnancy and other environmental stresses may overwhelm the heterozygous mother's capacity for effective metabolism of long chain fatty acids, leading to an accumulation of potentially toxic fatty acid metabolites in the maternal circulation with subsequent damage to the maternal liver.

Prospective Screening for Pediatric Mitochondrial Trifunctional Protein Defects in Pregnancies Complicated by Liver Disease

Obstetrical & Gynecological Survey: April 2003 - Volume 58 - Issue 4 - p 242-243 doi: 10.1097/01.OGX.0000058697.18516.A1

Prospective screening for pediatric mitochondrial trifunctional protein defects in pregnancies complicated by liver disease.

Acute fatty liver of pregnancy (AFLP) and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome are serious complications of pregnancy. Studies in families with recessively inherited mitochondrial trifunctional protein defects documented an association between these maternal illnesses and fetal deficiency of long-chain 3-hydroxyacyl coenzyme A dehydrogenase; this enzyme resides in the alpha subunit of the trifunctional protein and catalyzes the third step in long-chain fatty acid beta oxidation. To estimate the frequency of fetal long-chain 3-hydroxyacyl coenzyme A dehydrogenase deficiency in pregnancies complicated by AFLP or HELLP syndrome. Cohort study in which 108 consecutive blood samples from women who developed AFLP or HELLP syndrome, from their offspring, or from their partners were referred to our laboratory for molecular screening from January 1997 to December 2001. Twenty-seven women had AFLP and 81 had HELLP syndrome. We screened the DNA for mutations in the alpha subunit of the trifunctional protein. Presence of mutations that cause 3-hydroxyacyl coenzyme A dehydrogenase deficiency in the offspring. We detected mutations causing pediatric long-chain 3-hydroxyacyl coenzyme A dehydrogenase deficiency in 5 families (19%) with maternal history of AFLP (95% confidence interval, 9%-54%). The maternal allele carried a prevalent glutamic acid 474 to glutamine (E474Q) mutation. The paternal allele carried the E474Q mutation in 3 families and a stop codon mutation in the other 2 families. Only 1 woman with HELLP syndrome was heterozygous for the E474Q mutation; no mutations were detected in the newborn. The association between AFLP and the E474Q mutation in the fetus is significant. Screening newborns for this mutation in pregnancies complicated by AFLP could allow early diagnosis and treatment in newborns and genetic counseling and prenatal diagnosis in subsequent pregnancies in affected families.

Long-chain 3-hydroxyacyl–coenzyme A dehydrogenase deficiency with the G1528C mutation: Clinical presentation of thirteen patients

Long-chain 3-hydroxyacyl—coenzyme A (CoA) dehydrogenase is one of three enzyme activities of the mitochondrial trifunctional protein. We report the clinical findings of 13 patients with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. At presentation the patients had had hypoglycemia, cardiomyopathy, muscle hypotonia, and hepatomegaly during the first 2 years of life. Seven patients had recurrent metabolic crises, and six patients had a steadily progressive course. Two patients had cholestatic liver disease, which is uncommon in β-oxidation defects. One patient had peripheral neuropathy, and six patients had retinopathy with focal pigmentary aggregations or retinal hypopigmentation. All patients were homozygous for the common mutation G1528C. However, the enoyl-CoA hydratase and 3-ketoacyl-CoA thiolase activities of the mitochondrial trifunctional protein were variably decreased in skin fibroblasts. Dicarboxylic aciduria was detected in 9 of 10 patients, and most patients had lactic acidosis, increased serum creatine kinase activities, and low serum carnitine concentration. Neuroradiologically there was bilateral periventricular or focal cortical lesions in three patients, and brain atrophy in one. Only one patient, who has had dietary treatment for 9 years, is alive at the age of 14 years; all others died before they were 2 years of age. Recognition of the clinical features of long-chain 3-hydroxyacyl-CoA deficiency is important for the early institution of dietary management, which may alter the otherwise invariably poor prognosis. J Pediatr 1997;130:67-76

Acute fatty liver of pregnancy and long-chain 3-hydroxyacyl–coenzyme A dehydrogenase deficiency

The pathogenesis of acute fatty liver of pregnancy is unknown, but similarities in the clinical presentation and the histological appearance of the liver with those found in children with metabolic defects in the intramitochondrial beta-oxidation pathway of the liver suggest that a disturbance in hepatic fatty acid oxidation may play a role. We report a woman with acute fatty liver of pregnancy who gave birth to a seemingly normal full-term infant who was seen at 4 mo of age with hypoglycemia, coma and profound hepatic steatosis. The infant had a defect in fatty acid oxidation, long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency, and the mother proved to be heterozygous for this metabolic condition. We hypothesize that the interaction of an affected fetus with a female heterozygous for this defect in fatty acid oxidation in the late third trimester accounts for some cases of acute fatty liver of pregnancy.

Pregnancy and fetal long-chain 3-hydroxyacyl coenzyme A dehydrogenase deficiency.

We report on eleven pregnancies in 5 mothers. 6 of the babies had long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) deficiency, and each of the pregnancies was complicated by features such as fatty liver and HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome. By contrast, 3 of the mothers also gave birth to unaffected babies, and these pregnancies were largely uncomplicated. We conclude that there may be adverse effects on maternal liver function from a fetus with LCHAD deficiency. Heterozygosity in the mother cannot alone account for the adverse effects because of the segregation of these effects with fetal LCHAD status.

Medium‐ and long‐chain 3‐hydroxymonocarboxylic acids: Analysis by gas chromatography combined with mass spectrometry

Medium- and long-chain 3-hydroxymonocarboxylic acids represent intermediates in the beta-oxidation of fatty acids: they accumulate in the plasma of patients with an inherited deficiency of long-chain 3-hydroxyacylcoenzyme A dehydrogenase. 3-Hydroxy acids with chain lengths varying from 6 to 16 were synthesized by a Reformatzky reaction. Capillary gas chromatography of the pertrimethylsilyl derivatives was performed on a CP-Sil 19 CB column, coupled to a quadrupole mass spectrometer in the electron impact mode. Calculation of the retention indices showed that the separation of the 3-hydroxy acids from the homologous straight-chain fatty acids may be troublesome, stressing the need for mass spectrometric identification.