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Patricie Burda, Terttu Suormala, Dorothea Heuberger, Alexandra Schäfer, Brian Fowler, D Sean Froese, Matthias R Baumgartner
5,10-Methylenetetrahydrofolate reductase (MTHFR) catalyzes the NADPH-dependent reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate using FAD as the cofactor. Severe MTHFR deficiency is the most common inborn error of folate metabolism, resulting in hyperhomocysteinemia and homocystinuria. Approximately 70 missense mutations have been described that cause severe MTHFR deficiency, however, in most cases their mechanism of dysfunction remains unclear. Few studies have investigated mutational specific defects; most of these assessing only activity levels from a handful of mutations using heterologous expression...
October 14, 2016: Journal of Inherited Metabolic Disease
Miguel Oliveira Santos, Ruth Geraldes, Isabel Conceição
Classic homocystinuria is one of the most common causes of hereditary hyperhomocysteinemia. It is an autosomal recessive and multisystemic disorder due to cystathionine β-synthase deficiency. We described a case of an 18-year-old Portuguese man with an ischaemic stroke, who was subsequently diagnosed with classic homocystinuria [Thr191Met (c.572C>T) CBS mutation] associated with a sensorimotor neuropathy. The patient had a good clinical and metabolic response to pyridoxine plus methionine-restricted diet after 12 months of treatment...
2016: BMJ Case Reports
Funda Oztunc, Sezen Ugan Atik, Reyhan Dedeoglu, Firuze Erbek Alp, Selman Gokalp
Postural orthostatic tachycardia syndrome (POTS) is an abnormal heart rate response to a positional change. Several potential mechanisms for pathophysiology of POTS are defined. This syndrome can coexist with different clinical situations. In our report, the first case was a 13-year-old female who has been followed up for diagnosis of homocystinuria. She was admitted to our outpatient clinic with complaints of dizziness after suddenly moving from supine to upright position and chest pain after exercise. Tilt table test was performed to evaluate dizziness...
2016: Case Reports in Pediatrics
Meltem Erol, Ozlem Bostan Gayret, Ozgul Yigit, Kubra Serefoglu Cabuk, Mehmet Toksoz, Mahir Tiras
INTRODUCTION: Homocystinuria is a hereditary disease caused by a defect in the enzymes involved in metabolizing methionine. Homocystinuria can influence many systems and may be mistaken for other diseases, including Moyamoya disease. Here, we report the case of a 10-year-old male patient with a diagnosis of Moyamoya disease who had been monitored for that for an extended period. The patient's diagnosis was changed to homocystinuria as a result of lens subluxation and cataract findings...
April 2016: Iranian Red Crescent Medical Journal
Jürgen G Okun, Hongying Gan-Schreier, Tawfeq Ben-Omran, Kathrin V Schmidt, Junmin Fang-Hoffmann, Gwendolyn Gramer, Ghassan Abdoh, Noora Shahbeck, Hilal Al Rifai, Abdul Latif Al Khal, Gisela Haege, Chuan-Chi Chiang, David C Kasper, Bridget Wilcken, Peter Burgard, Georg F Hoffmann
BACKGROUND: In classical homocystinuria (HCU, MIM# 236200) due to the deficiency of cystathionine β-synthase (EC there is a clear evidence for the success of early treatment. The aim of this study was to develop and evaluate a two-tier strategy for HCU newborn screening. METHODS: We reevaluated data from our newborn screening programme for Qatar in a total number of 125,047 neonates including 30 confirmed HCU patients. Our hitherto existing screening strategy includes homocysteine (Hcy) measurements in every child, resulting in a unique dataset for evaluation of two-tier strategies...
June 21, 2016: JIMD Reports
S Cotard, A Nouni, V Jaquinandi, G Gladu, A Kaladji, G Mahé
Peripheral arterial disease (PAD) encompasses disease of all arteries of the body except the coronary arteries. The main etiology whatever the patient's age is atherosclerosis. Different etiologies can induce PAD especially when patients are younger than 50 years old and have no cardiovascular risk factors (smoking, hypertension, diabetes…). PAD that appears before 50 years old can be named juvenile PAD (JPAD) although there is no consensus about the definition. The aim of this work is to present the different etiologies of JPAD according to their hereditary, acquired or mixed origins...
September 2016: Annales de Cardiologie et D'angéiologie
Bodo B Beck, FrancJan van Spronsen, Arjan Diepstra, Rolf M F Berger, Martin Kömhoff
Methylmalonic aciduria and homocystinuria, cobalamin C (cblC) type, is the most common genetic type of functional cobalamin (vitamin B12) deficiency. This metabolic disease is characterized by marked heterogeneity of neurocognitive disease (microcephaly, seizures, developmental delay, ataxia, hypotonia) and variable extracentral nervous system involvement (failure to thrive, cardiovascular, renal, ocular) manifesting predominantly early in life, sometimes during gestation. To enhance awareness and understanding of renal disease associated with cblC defect, we studied biochemical, genetic, clinical, and histopathological data from 36 patients...
June 11, 2016: Pediatric Nephrology: Journal of the International Pediatric Nephrology Association
Juan A Siordia, Jimena Franco, Todd R Golden, Bilal Dar
PURPOSE OF REVIEW: Pseudoexfoliation syndrome (PEX) is a common cause of open-angle glaucoma that is characterized by stress-induced elastic microfibrillopathy related to an accumulation of matrix metalloproteinases. The accumulation of matrix metalloproteinases increases deposition of protein substance within ocular structures and other organs including the heart. Many studies have associated the presence of cardiovascular disease with pseudoexfoliation syndrome, but much debate exists between studies in terms of significant relationships...
July 2016: Current Cardiology Reports
Erez M Bublil, Tomas Majtan, Insun Park, Richard S Carrillo, Helena Hůlková, Jakub Krijt, Viktor Kožich, Jan P Kraus
Homocystinuria, which typically results from cystathionine β-synthase (CBS) deficiency, is the most common defect of sulfur amino acid metabolism. CBS condenses homocysteine and serine to cystathionine that is then converted to cysteine. Individuals with homocystinuria have markedly elevated plasma levels of homocysteine and methionine and reduced concentrations of cystathionine and cysteine. Clinical disease manifestations include thromboembolism and neuropsychiatric, ocular, and skeletal complications. Here, we have shown that administration of PEGylated CBS into the circulation of homocystinuria model mice alters the extra- and intracellular equilibrium of sulfur amino acids, resulting in a decrease of approximately 75% in plasma total homocysteine (tHcy) and normalization of cysteine concentrations...
June 1, 2016: Journal of Clinical Investigation
Dwight D Koeberl
Inherited metabolic disorders are often characterized by the lack of an essential enzyme and are currently treated by dietary restriction and other strategies to replace the substrates or products of the missing enzyme. Patients with homocystinuria lack the enzyme cystathionine β-synthase (CBS), and many of these individuals do not respond to current treatment protocols. In this issue of the JCI, Bublil and colleagues demonstrate that enzyme replacement therapy (ERT) provides long-term amelioration of homocystinuria-associated phenotypes in CBS-deficient murine models...
June 1, 2016: Journal of Clinical Investigation
Harvey L Levy
Harvey Mudd was the father of methionine metabolic disorders. Beginning with his identification of the enzyme defect in homocystinuria, he co-discovered cobalamin C disorder as the first known human disorder of vitamin B12 metabolism, thereby extending our concept of homocystinuria as a key feature of related disorders rather than a single disease, and identified new disorders that produce hypermethioninemia. He had no equal in our understanding of how critical methionine metabolism is to human homeostasis.
July 2016: Molecular Genetics and Metabolism
Brooke Levenseller Levin, Elizabeth Varga
The 5, 10 methylenetetrahydrofolate reductase (MTHFR) enzyme is a catalyst in the folate metabolism pathway, the byproducts of which are involved in the remethylation of homocysteine to methionine. Methionine is a precursor for a major DNA methyl donor and is important for DNA methylation and gene regulation. Rare mutations in the MTHFR gene have been associated with autosomal recessive MTHFR deficiency leading to homocystinuria. In addition, two polymorphic variants in this gene (C677T and A1298C) have been implicated in a mild form of MTHFR deficiency associated with hyperhomocysteinemia...
October 2016: Journal of Genetic Counseling
Tarun Kumar, Gurumayum Suraj Sharma, Laishram Rajendrakumar Singh
Homocystinuria is a disorder of sulfur metabolism pathway caused by deficiency of cystathionine β-synthase (CBS). It is characterized by increased accumulation of homocysteine (Hcy) in the cells and plasma. Increased homocysteine results in various vascular and neurological complications. Present strategies to lower cellular and plasma homocysteine levels include vitamin B6 intake, dietary methionine restriction, betaine supplementation, folate and vitamin B12 administration. However, these strategies are inefficient for treatment of homocystinuria...
July 1, 2016: Clinica Chimica Acta; International Journal of Clinical Chemistry
Cristy A Ku, Jacqueline K Ng, Daniel J Karr, Leah Reznick, Cary O Harding, Richard G Weleber, Mark E Pennesi
BACKGROUND: Cobalamin C disease (cblC), which leads to methylmalonic acidemia with homocystinuria, is the most common inherited disorder of vitamin B12 metabolism. Reported ocular findings associated with cblC have been maculopathy, pigmentary retinopathy, and optic nerve atrophy. Cobalamin A disease (cblA) which causes an isolated methylmalonic acidemia without homocystinuria is rarer than cblC. This is the first detailed report of the ocular findings associated with cblA. We also describe the spectrum of ocular findings in our cblC patients...
March 15, 2016: Ophthalmic Genetics
Ainhoa Martínez-Pizarro, Lourdes R Desviat, Magdalena Ugarte, Belén Pérez, Eva Richard
Proper function of endoplasmic reticulum (ER) and mitochondria is crucial for cellular homeostasis, and dysfunction at either site as well as perturbation of mitochondria-associated ER membranes (MAMs) have been linked to neurodegenerative and metabolic diseases. Previously, we have observed an increase in ROS and apoptosis levels in patient-derived fibroblasts with remethylation disorders causing homocystinuria. Here we show increased mRNA and protein levels of Herp, Grp78, IP3R1, pPERK, ATF4, CHOP, asparagine synthase and GADD45 in patient-derived fibroblasts suggesting ER stress and calcium perturbations in homocystinuria...
2016: PloS One
Tomas Majtan, Angel L Pey, June Ereño-Orbea, Luis Alfonso Martínez-Cruz, Jan P Kraus
Classical homocystinuria (HCU) is the most common loss-of-function inborn error of sulfur amino acids metabolism. HCU is caused by a deficiency in enzymatic degradation of homocysteine, a toxic intermediate of methionine transformation to cysteine, chiefly due to missense mutations in the cystathionine betasynthase (CBS) gene. As with many other inherited disorders, the pathogenic mutations do not target key catalytic residues, but rather introduce structural perturbations leading to an enhanced tendency of the mutant CBS to misfold and either to form non-functional aggregates or to undergo proteasome-dependent degradation...
2016: Current Drug Targets
Mikael Oscarson, Daphne Vassiliou, Anna Nordenström, Ricard Nergårdh, Anna Wedell, Ulrika von Döbeln
Inherited metabolic diseases usually present in the neonatal period or before school age. A growing portion of the disorders can be treated successfully, and an increasing number of patients are now treated in adult medicine. Several of the disorders also exist as attenuated variants without distinct symptoms in childhood. They can present as an acute onset event during metabolic stress in adulthood. We describe three patients with acute clinical decompensation in adulthood with severe sequelae and propose investigations to help diagnose such patients...
2016: Läkartidningen
Min-Ah Woo, Jung Hun Park, Daeyeon Cho, Sang Jun Sim, Moon Il Kim, Hyun Gyu Park
We developed a whole-cell surface plasmon resonance (SPR) sensor based on a leucine auxotroph of Escherichia coli displaying a gold-binding protein (GBP) in response to cell growth and applied this sensor to the diagnosis of maple syrup urine disease, which is represented by the elevated leucine level in blood. The leucine auxotroph was genetically engineered to grow displaying GBP in a proportion to the concentration of target amino acid leucine. The GBP expressed on the surface of the auxotrophs directly bound to the golden surface of an SPR chip without the need for any additional treatment or reagents, which consequently produced SPR signals used to determine leucine levels in a test sample...
March 1, 2016: Analytical Chemistry
Tomas Majtan, Angel L Pey, Jan P Kraus
Many pathogenic missense mutations in human cystathionine beta-synthase (CBS) cause misfolding of the mutant enzyme resulting in aggregation or rapid degradation of the protein. Subsequent loss of CBS function leads to CBS-deficient homocystinuria (CBSDH). CBS contains two sets of binding sites for S-adenosylmethionine (SAM) that independently regulate the enzyme activity and kinetically stabilize its regulatory domain. In the present study, we examined the hypothesis that CBS activation may be decoupled from kinetic stabilization and thus CBS regulatory domain can serve as a novel drug target for CBSDH...
July 2016: Biochimie
Viktor Kožich, Jakub Krijt, Jitka Sokolová, Petra Melenovská, Pavel Ješina, Roman Vozdek, Tomáš Majtán, Jan P Kraus
Two enzymes in the transsulfuration pathway of homocysteine -cystathionine beta-synthase (CBS) and gamma-cystathionase (CTH)-use cysteine and/or homocysteine to produce the important signaling molecule hydrogen sulfide (H2S) and simultaneously the thioethers lanthionine, cystathionine or homolanthionine. In this study we explored whether impaired flux of substrates for H2S synthesis and/or deficient enzyme activities alter production of hydrogen sulfide in patients with homocystinurias. As an indirect measure of H2S synthesis we determined by LC-MS/MS concentrations of thioethers in plasma samples from 33 patients with different types of homocystinurias, in 8 patient derived fibroblast cell lines, and as reaction products of seven purified mutant CBS enzymes...
July 2016: Biochimie
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