Congenital disorders of glycosylation (CDG) and mitochondrial diseases are multisystem disorders with clinical characteristics that may overlap. We present four patients with CDG whose phenotypes ...suggested the diagnosis of a mitochondrial disease. Patients 1 and 2 are siblings with hemiplegic headache, stroke-like episodes, lactic acidaemia and history of maternal migraine; their initial clinical diagnosis was MELAS syndrome (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes). Patient 3 suffers from ataxia, neuropathy, ophtalmoplegia and retinitis pigmentosa suggestive of NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. Patient 4 presented with neurological regression mimicking Leigh disease, with ptosis, myoclonus, ataxia and brainstem and cerebellar atrophy. Screening for mitochondrial disease including enzyme and mtDNA investigations on muscle biopsy were performed on Patients 1, 2 and 4 with normal results. However, evidence for a glycosylation disorder was substantiated by an increased carbohydrate deficient transferrin (CDT). The isoelectric focussing pattern of serum sialotransferrin was typical of CDG type I in Patients 1, 2 and 3 and was shifted towards the less sialylated bands in case 4. A deficiency of phosphomanomutase (PMM) confirmed the diagnosis of CDG-Ia in Patients 1, 2 and 3, who are compound heterozygous for mutations R141H / T237M (Patients 1 and 2) and R141H/P113L (Patient 3). In Patient 4, PMM activity was normal, and further enzymatic and molecular studies are underway. As the search for the primary defect in mitochondrial diseases is often unsuccessful, the pool of mitochondrial patients that remain without definite diagnosis might include CDG cases. Routine screening for CDG may avoid precocious invasive investigations.
Hereditary motor and sensory neuropathy russe, a form of autosomal recessive Charcot–Marie–Tooth disease, is a rare disorder found in several Roma families from Europe. The gene has been mapped to a ...1
Mb region on 10q22. Detailed analysis led to the exclusion of 22 candidate genes and the assembly of a high-density genetic map comprising 141 polymorphic markers. Extensive genotyping in an extended sample of affected families resulted in a 10-fold reduction of the critical hereditary motor and sensory neuropathy russe gene region, which is now contained within a single completely sequenced BAC clone. The fact that no sequence variant has been detected in the known genes in the critical region indicates that the hereditary motor and sensory neuropathy russe mutation affects a novel gene that remains to be identified.
Hereditary motor and sensory neuropathy type Lom, initially identified in Roma (Gypsy) families from Bulgaria, has been mapped to 8q24. Further refined mapping of the region has been undertaken on ...DNA from patients diagnosed across Europe. The refined map consists of 25 microsatellite markers over approximately 3 cM. In this collaborative study we have identified a number of historical recombinations resulting from the spread of the hereditary motor and sensory neuropathy type Lom gene through Europe with the migration and isolation of Gypsy groups. Recombination mapping and the minimal region of homozygosity reduced the original 3 cM hereditary motor and sensory neuropathy type Lom region to a critical interval of about 200 kb.
Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive muscular dystrophy with primary gamma-sarcoglycan deficiency, generally associated with a severe clinical course. ...gamma-sarcoglycan, a 35kDa dystrophin-associated protein, is encoded by a single gene on chromosome 13q12. Six different mutations have been described in that gene, and it has been proved they are the origin of the disease. One of these mutations (C283Y), a G-->A transition in codon 283, was recently and exclusively identified in Gypsy patients from different European countries. We report the study of 11 LGMD2C unrelated Gypsy families (nine Spanish and two Portugese). The muscle biopsies of these patients showed a drastically decreased immunostaining with alpha and gamma-sarcoglycan antibodies. All the patients were homozygous for C283Y missense mutation, and all affected chromosomes (patients and heterozygous relatives) carried the allele 5 (112 bp) of the intragenic microsatellite D13S232. Unexpectedly, this allele is most frequent in the Caucasian population but not in the normal Gypsy population. The clinical severity of all patients demonstrates that the C283Y missense mutation in a homozygous state causes a severe LGMD2C (DMD-like). The elevated number of families ascertained let us assume that LGMD2C is prevalent in the Gypsy population, and that all the families have inherited a founding mutation.
We present 2 cases of progressively severe Kearns-Sayre syndrome (KSS) with multisystemic affectation and atypical endocrine and cutaneous features, a 16-year-old patient (case 1) and a 5-year-old ...patient (case 2). Endocrine studies showed high glucose and glycohemoglobin concentrations with normal pancreatic reserve and low values of ACTH, cortisol, LH and FSH in case 1. Normal ACTH values with low concentrations of cortisol and PTH were observed in case 2. Southern blot analysis and PCR amplification revealed the presence of a deletion of approximately 6.7 kb in the mitochondrial DNA of both patients. Endocrinological studies suggest that adrenal insufficiency may be an additional feature of KSS that worsens the clinical evolution of the patients. In spite of a normal pancreatic reserve, insulin therapy should be considered in patients with diabetes mellitus of mitochondrial origin.
A new point mutation in exon 12 of the dystrophin gene was identified in a DMD patient using multiple SSCP analysis, which allows the simultaneous study of several exons. The mutation is an A ...insertion at position 1580 of the cDNA sequence, leading to a stop codon in the translational reading frame. This mutation was not observed in a sample of 70 DMD patients.
We report a case of a mixed sensorimotor, predominantly axonal mononeuritis multiplex that developed after a severe meningococcal septicemia and disseminated intravascular coagulation (DIC) with ...associated distal limb necrosis. Ischemia resulting from the DIC-induced multiple vascular occlusions is suggested as the leading cause of this neuropathy.
Smoking increases the risk of many diseases and could act through changes in DNA methylation patterns. The aims of this study were to determine the association between smoking and DNA methylation ...throughout the genome at cytosine-phosphate-guanine (CpG) site level and genomic regions. A discovery cross-sectional epigenome-wide association study nested in the follow-up of the REGICOR cohort was designed and included 645 individuals. Blood DNA methylation was assessed using the Illumina HumanMethylation450 BeadChip. Smoking status was self-reported using a standardized questionnaire. We identified 66 differentially methylated CpG sites associated with smoking, located in 38 genes. In most of these CpG sites, we observed a trend among those quitting smoking to recover methylation levels typical of never smokers. A CpG site located in a novel smoking-associated gene (cg06394460 in LNX2) was hypomethylated in current smokers. Moreover, we validated two previously reported CpG sites (cg05886626 in THBS1, and cg24838345 in MTSS1) for their potential relation to atherosclerosis and cancer diseases, using several different approaches: CpG site methylation, gene expression, and plasma protein level determinations. Smoking was also associated with higher THBS1 gene expression but with lower levels of thrombospondin-1 in plasma. Finally, we identified differential methylation regions in 13 genes and in four non-coding RNAs. In summary, this study replicated previous findings and identified and validated a new CpG site located in LNX2 associated with smoking.
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