van Kuilenburg A.B.P.,Metabolic |
Dobritzsch D.,Karolinska Institutet |
Meijer J.,Metabolic |
Meinsma R.,Metabolic |
And 17 more authors.
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2010
Dihydropyrimidinase (DHP) is the second enzyme of the pyrimidine degradation pathway and catalyses the ring opening of 5,6-dihydrouracil and 5,6-dihydrothymine. To date, only 11 individuals have been reported suffering from a complete DHP deficiency. Here, we report on the clinical, biochemical and molecular findings of 17 newly identified DHP deficient patients as well as the analysis of the mutations in a three-dimensional framework. Patients presented mainly with neurological and gastrointestinal abnormalities and markedly elevated levels of 5,6-dihydrouracil and 5,6-dihydrothymine in plasma, cerebrospinal fluid and urine. Analysis of DPYS, encoding DHP, showed nine missense mutations, two nonsense mutations, two deletions and one splice-site mutation. Seventy-one percent of the mutations were located at exons 5-8, representing 41% of the coding sequence. Heterologous expression of 11 mutant enzymes in Escherichia coli showed that all but two missense mutations yielded mutant DHP proteins without significant activity. Only DHP enzymes containing the mutations p.R302Q and p.T343A possessed a residual activity of 3.9% and 49%, respectively. The crystal structure of human DHP indicated that the point mutations p.R490C, p.R302Q and p.V364M affect the oligomerization of the enzyme. In contrast, p.M70T, p.D81G, p.L337P and p.T343A affect regions near the di-zinc centre and the substrate binding site. The p.S379R and p.L7V mutations were likely to cause structural destabilization and protein misfolding. Four mutations were identified in multiple unrelated DHP patients, indicating that DHP deficiency may be more common than anticipated. © 2010 Elsevier B.V.
Pampols T.,Institute Of Bioquimica Clinica
Advances in Experimental Medicine and Biology | Year: 2010
Inherited metabolic disorders (IMD) represent a vast, diverse and heterogeneous collection of around 700 genetic diseases. They are caused by rare mutations that affect the function of individual proteins and are a significant cause of morbidity and mortality, especially in childhood. Difficulties in ascertaining cases and the increasing number of new disorders have hampered efforts to accumulate exhaustive epidemiological data. Nonetheless, recent studies quote the cumulative incidence of IMDs at around 1 in 800 live births. To understand the epidemiology of IMD we will consider in this chapter two types of epidemiological approaches. The first type, or the Analytical approaches, includes the function of genetic factors in the natural history and clinical variability of the disease, as well as the role of epigenetic, stochastic and environmental factors. The second type, or the Descriptive approaches, comprises methods of case ascertainment through the diagnosis of symptomatic patients and population screening, mainly newborn and carrier screening, as well as measures of disease frequency and resources for disease control and prevention (primary, secondary and tertiary). © Springer Science+Business Media B.V. 2010.
Pineda M.,Hospital Sant Joan de Deu |
Pineda M.,Research Center Biomedica En Red Of Enfermedades Raras Ciberer |
Montero R.,Research Center Biomedica En Red Of Enfermedades Raras Ciberer |
Aracil A.,Hospital Sant Joan de Deu |
And 14 more authors.
Movement Disorders | Year: 2010
We assessed the clinical outcome after coenzyme Q10 (CoQ 10) therapy in 14 patients presenting ataxia classified into two groups according to CoQ10 values in muscle (deficient or not). We performed an open-label prospective study: patients were evaluated clinically (international cooperative ataxia rating scale [ICARS] scale, MRI, and videotape registration) at baseline and every 6 months during a period of 2 years after CoQ10 treatment (30 mg/kg/day). Patients with CoQ10 deficiency showed a statistically significant reduction of ICARS scores (Wilcoxon test: P = 0.018) after 2 years of CoQ10 treatment when compared with baseline conditions. In patients without CoQ10 deficiency, no statistically significant differences were observed in total ICARS scores after therapy, although 1 patient from this group showed a remarkable clinical amelioration. Biochemical diagnosis of CoQ10 deficiency was a useful tool for the selection of patients who are good candidates for treatment as all of them responded to therapy. However, the remarkable clinical response in 1 case without CoQ10 deficiency highlights the importance of treatment trials for identification of patients with CoQ10-responsive ataxia. © 2010 Movement Disorder Society.
Launay N.,Bellvitge Biomedical Research Institute IDIBELL |
Launay N.,Idibell Hospital Universitari Of Bellvitge |
Launay N.,Center for Biomedical Research on Rare Diseases |
Aguado C.,Center for Biomedical Research on Rare Diseases |
And 26 more authors.
Acta Neuropathologica | Year: 2014
X-linked adrenoleukodystrophy (X-ALD) is a rare neurometabolic disease characterized by the accumulation of very long chain fatty acids (VLCFAs) due to a loss of function of the peroxisomal transporter ABCD1. Here, using in vivo and in vitro models, we demonstrate that autophagic flux was impaired due to elevated mammalian target of rapamycin (mTOR) signaling, which contributed to X-ALD pathogenesis. We also show that excess VLCFAs downregulated autophagy in human fibroblasts. Furthermore, mTOR inhibition by a rapamycin derivative (temsirolimus) restored autophagic flux and inhibited the axonal degenerative process as well as the associated locomotor impairment in the Abcd1−/Abcd2−/− mouse model. This process was mediated through the restoration of proteasome function and redox as well as metabolic homeostasis. These findings provide the first evidence that links impaired autophagy to X-ALD, which may yield a therapy based on autophagy activators for adrenomyeloneuropathy patients. © 2014, The Author(s).
Flanagan J.M.,Childrens University Hospital |
Flanagan J.M.,Royal College of Surgeons in Ireland |
McMahon G.,Royal College of Surgeons in Ireland |
Brendan Chia S.H.,Royal College of Surgeons in Ireland |
And 19 more authors.
Heredity | Year: 2010
Classical or transferase-deficient galactosaemia is an inherited metabolic disorder caused by mutation in the human Galactose-1-phosphate uridyl transferase (GALT) gene. Of some 170 causative mutations reported, fewer than 10% are observed in more than one geographic region or ethnic group. To better understand the population history of the common GALT mutations, we have established a haplotyping system for the GALT locus incorporating eight single nucleotide polymorphisms and three short tandem repeat markers. We analysed haplotypes associated with the three most frequent GALT gene mutations, Q188R, K285N and Duarte-2 (D2), and estimated their age. Haplotype diversity, in conjunction with measures of genetic diversity and of linkage disequilibrium, indicated that Q188R and K285N are European mutations. The Q188R mutation arose in central Europe within the last 20 000 years, with its observed east-west cline of increasing relative allele frequency possibly being due to population expansion during the re-colonization of Europe by Homo sapiens in the Mesolithic age. K285N was found to be a younger mutation that originated in Eastern Europe and is probably more geographically restricted as it arose after all major European population expansions. The D2 variant was found to be an ancient mutation that originated before the expansion of Homo sapiens out of Africa. © 2010 Macmillan Publishers Limited. All rights reserved.