Refine
Departments, institutes and facilities
Document Type
- Article (124)
- Part of a Book (3)
- Preprint (2)
Year of publication
Keywords
- Organic aciduria (5)
- Inborn error of metabolism (4)
- Ketolysis (4)
- organic aciduria (4)
- Ketogenesis (3)
- Ketone body (3)
- Metabolic acidosis (3)
- metabolic acidosis (3)
- 3-hydroxyisobutyrate dehydrogenase (2)
- 3-hydroxyisobutyric aciduria (2)
Dihydropyrimidine dehydrogenase (DPD) deficiency is an infrequently described autosomal recessive disorder of the pyrimidine degradation pathway and can lead to mental and motor retardation and convulsions. DPD deficiency is also known to cause a potentially lethal toxicity following administration of the antineoplastic agent 5-fluorouracil. In an ongoing study of 72 DPD deficient patients, we analysed the molecular background of 5 patients in more detail in whom initial sequence analysis did not reveal pathogenic mutations. In three patients, a 13.8 kb deletion of exon 12 was found and in one patient a 122 kb deletion of exon 14–16 of DPYD. In the fifth patient, a c.299_302delTCAT mutation in exon 4 was found and also loss of heterozygosity of the entire DPD gene. Further analysis demonstrated a de novo deletion of approximately 14 Mb of chromosome 1p13.3–1p21.3, which includes DPYD. Haploinsufficiency of NTNG1, LPPR4, GPSM2, COL11A1 and VAV3 might have contributed to the severe psychomotor retardation and unusual craniofacial features in this patient. Our study showed for the first time the presence of genomic deletions affecting DPYD in 7% (5/72) of all DPD deficient patients. Therefore, screening of DPD deficient patients for genomic deletions should be considered.
Mitochondrial neurogastrointestinal encephalomyopathy is an autosomal recessive disorder in which a nuclear mutation of the thymidine phosphorylase gene leads to mitochondrial genomic dysfunction. Herein, we report a 29-year-old Iranian man with abdominal pain, diarrhea, hearing loss, ophthalmoplegia, sensorimotor axonal neuropathy, and elevated muscle enzymes. Magnetic resonance imaging showed leukoencephalopathic changes. Metabolite analysis revealed a very high thymidine concentration in the patient's urine consistent with the diagnosis of mitochondrial neurogastrointestinal encephalomyopathy.
Amaç: Keton cisim oluşumu (ketogenez) bozuklukları; mitokondriyel 3-hidroksi-3metil glutaril CoA sentaz (Mhs) ve 3-hidroksi-3-metil glutaril CoA liyaz (HL) enzim eksiklikleri sonucu oluşur. Keton cisim yıkımı (ketoliz) bozuklukları ise suksinil CoA: 3 oksoasit CoA transferaz (SCOT) ve asetoasetil CoA thiolaz-beta ketotiolaz (MAT) enzim eksiklikleri sonucu oluşmaktadır. Keton metabolizma bozukluğu tanısıyla izlenen hastaların klinik ve laboratuvar bulguları ile değerlendirilmesi amaçlandı.
Yöntem: Keton metabolizması bozukluğu tanısıyla izlenen hasta verileri retrospektif olarak incelendi.
Bulgular: Dört hastada HL eksikliği, 3 hastada MAT eksikliği ve 2 hastada SCOT eksikliği tanısı mevcuttu. Hastaların ortanca yaşı 5 yıl (6 ay-15,5 yıl), ilk metabolik dekompanzasyon atak yaşı ortalama 7,7 ay (22 gün-19 ay) idi. MAT eksikliği olan bir hasta, kardeş taraması ile asemptomatik dönemde tanı aldı. İki hastada spastik tetraparezi gibi ağır nörolojik defisit gelişti. Dekompanzasyon ataklarının beslenememe, kusma ve gastroenterit gibi infeksiyon sonrası geliştiği görüldü.
Sonuç: Açıklanamayan metabolik asidoz atakları durumunda keton metabolizma bozuklukları akılda tutulmalıdır. Akut dekompanzasyon değişik yaşlarda ortaya çıkabilir, klinik şiddeti değişken olabilir. Erken tanı ve uygun tedavi mortalite ve morbidite açısından çok önemlidir.
A structural mapping of mutations causing succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency
(2013)
Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is a rare inherited metabolic disorder of ketone metabolism, characterized by ketoacidotic episodes and often permanent ketosis. To date there are ~20 disease-associated alleles on the OXCT1 gene that encodes the mitochondrial enzyme SCOT. SCOT catalyzes the first, rate-limiting step of ketone body utilization in peripheral tissues, by transferring a CoA moiety from succinyl-CoA to form acetoacetyl-CoA, for entry into the tricarboxylic acid cycle for energy production. We have determined the crystal structure of human SCOT, providing a molecular understanding of the reported mutations based on their potential structural effects. An interactive version of this manuscript (which may contain additional mutations appended after acceptance of this manuscript) may be found on the web address:
http://www.thesgc.org/jimd/SCOT
Propionic acidemia in a previously healthy adolescent with acute onset of dilated cardiomyopathy
(2014)
There is an unmet need for the development and validation of biomarkers and surrogate endpoints for clinical trials in propionic acidemia (PA) and methylmalonic acidemia (MMA). This review examines the pathophysiology and clinical consequences of PA and MMA that could form the basis for potential biomarkers and surrogate endpoints. Changes in primary metabolites such as methylcitric acid (MCA), MCA:citric acid ratio, oxidation of 13C-propionate (exhaled 13CO2), and propionylcarnitine (C3) have demonstrated clinical relevance in patients with PA or MMA. Methylmalonic acid, another primary metabolite, is a potential biomarker, but only in patients with MMA. Other potential biomarkers in patients with either PA and MMA include secondary metabolites, such as ammonium, or the mitochondrial disease marker, fibroblast growth factor 21. Additional research is needed to validate these biomarkers as surrogate endpoints, and to determine whether other metabolites or markers of organ damage could also be useful biomarkers for clinical trials of investigational drug treatments in patients with PA or MMA. This review examines the evidence supporting a variety of possible biomarkers for drug development in propionic and methylmalonic acidemias.
Methylmalonic and propionic acidemia (MMA/PA) are inborn errors of metabolism characterized by accumulation of propionic acid and/or methylmalonic acid due to deficiency of methylmalonyl-CoA mutase (MUT) or propionyl-CoA carboxylase (PCC). MMA has an estimated incidence of ~ 1: 50,000 and PA of ~ 1:100'000 -150,000. Patients present either shortly after birth with acute deterioration, metabolic acidosis and hyperammonemia or later at any age with a more heterogeneous clinical picture, leading to early death or to severe neurological handicap in many survivors. Mental outcome tends to be worse in PA and late complications include chronic kidney disease almost exclusively in MMA and cardiomyopathy mainly in PA. Except for vitamin B12 responsive forms of MMA the outcome remains poor despite the existence of apparently effective therapy with a low protein diet and carnitine. This may be related to under recognition and delayed diagnosis due to nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity.
Screening in clinical trials
(2002)
3-Hydroxyisobutyrate Dehydrogenase (HIBADH) deficiency - a novel disorder of valine metabolism
(2021)
3-Hydroxyisobutyric acid (3HiB) is an intermediate in the degradation of the branched-chain amino acid valine. Disorders in valine degradation can lead to 3HiB accumulation and its excretion in the urine. This article describes the first two patients with a new metabolic disorder, 3-hydroxyisobutyrate dehydrogenase (HIBADH) deficiency, its phenotype and its treatment with a low-valine diet. The detected mutation in the HIBADH gene leads to nonsense-mediated mRNA decay of the mutant allele and to a complete loss-of-function of the enzyme. Under strict adherence to a low-valine diet a rapid decrease of 3HiB excretion in the urine was observed. Due to limited patient numbers and intrafamilial differences in phenotype with one affected and one unaffected individual, the clinical phenotype of HIBADH deficiency needs further evaluation.