Clinical and genetic spectrum of an orphan disease MPAN: a series with new variants and a novel phenotype

Introduction. Pathogenic variations in C19orf12 are responsible for two allelic diseases: mitochondrial membrane protein-associated neurodegeneration (MPAN); and spastic paraplegia type 43 (SPG43). MPAN is an orphan disease, which presents with spasticity, dystonia, peripheral nerve involvement, and dementia. The pattern of iron accumulation on brain MRI may be a clue for the diagnosis of MPAN. SPG43, on the other hand, is characterised by progressive lower limb spasticity without brain iron accumulation. We here present clinical and genetic findings of MPAN patients with potentially pathogenic C19orf12 variants.Materials and methods. Patients from 13 different families having progressive motor symptoms with irritative pyramidal signs and brain iron accumulation were screened for C19orf12 gene variants.Results. C19orf12 screening identified seven variants associated with MPAN in eight patients from seven families. We associated two pathogenic variants (c.24G > C; p.(Lys8Asn) and c.194G > A; p.(Gly65Glu)) with the MPAN phenotype for the first time. We also provided a genetic diagnosis for a patient with an atypical MPAN presentation. The variant c.32C > T; p.(Thr11Met), common to Turkish adult-onset MPAN patients, was also detected in two unrelated late-onset MPAN patients.Conclusions. Genetic analysis along with thorough clinical analysis supported by radiological findings will aid the differential diagnosis of MPAN within the neurodegeneration with brain iron accumulation spectrum as well as other disorders including hereditary spastic paraplegia. Dystonia and parkinsonism may not be the leading clinical findings in MPAN patients, as these are absent in the atypical case. Finally, we emphasise that the existence of frameshifting variants may bias the age of onset toward childhood

CYP2D6 and CYP1A1 mutations in the Turkish population

Drugs and carcinogens are substrates of a group of metabolic enzymes including cytochrome p450 enzymes and gluthatione S-transferases. Many of the genes encoding these enzymes exhibit functional polymorphisms that contribute individual cancer susceptibility and drug response. Molecular studies based on these polymorphic enzymes also explain the aetiology of cancer and therapeutic management in clinics. We analysed the cytochrome p4501A1 (CYP1A1) and 2D6 (CYP2D6) variant genotype and allele frequencies by PCR-RFLP in Turkish individuals (n = 140). The frequency of the CYP1A1*2A mutant allele was found to be 15.4%, and the CYP2D6*3 and *4 mutant allele (poor metabolizer) frequencies were 2.5% and 13.9%, respectively. This study presents the first results of CYP1A1 and CYP2D6 mutant allele distributions in the Turkish population and these data provide an understanding of epidemiological studies that correlate therapeutic approaches and aetiology of several types of malignancy in Turkish patients. Copyright (C) 2005 John Wiley Sons, Ltd

Allele distribution data of nine short tandem repeat loci for Turkish population: WS1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820

Allele and genotype frequencies for the nine loci D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 were determined for 310 unrelated Turkish individuals

Role of CYP2D6, CYP1A1, CYP2E1, GSTT1, and GSTM1 genes in the susceptibility to acute leukemias

Acute leukemias (ALs) are heterogeneous diseases. Functional polymorphisms in the genes encoding detoxification enzymes cause inter-individual differences, which contribute to leukemia susceptibility. The CYP2D6, CYP1A1, CYP2E1, GSTT1, and GSTM1 polymorphisms in ALL (n = 156) and AML (n = 94) patients and 140 healthy controls were genotyped by PCR and/or PCR-RFLP using blood or bone marrow samples. No association was observed between the GSTT1 gene deletion and patients (OR = 0.8, 95% CI = 0.4-1.7 for AMLs and OR = 0.9, 95% CI = 0.5-1.6 for ALLs). Patients with ALL and AML had a higher prevalence of the GSTM1 deletions compared to controls but only the difference among adult AML patients (OR = 2.1, 95% Cl = 1.0-4.2) was statistically significant. The CYP2D6*3 variant allele frequency was lower in the overall acute leukemia patients (0.6%) compared to controls (P = 0.03). CYP2D6*1/*3 genotype frequency also showed a protective association in AML patients (OR = 0.09, 95% Cl = 0.01-1.7; P = 0.04). We also found a risk association for CYP2E1*5 in ALL and AML (OR = 3.6, 95% Cl = 1.4-9.4 and OR = 3.9, 95% Cl = 1.4-10.5, respectively). No association was found for the studied CYP2D6*4, CYP1A1 *2A, and GSTT1 "null" variants and the risk of acute leukemia (ALL or AML). This case-control study suggests a contribution of CYP2E1, CYP2D6, and GSTM1 "null" variants to the development of acute leukemias

Coagulation factor V gene mutation increases the risk of venous thrombosis in Behcet's disease

We investigated the prevalence of the coagulation factor V gene G1691A mutation in 64 patients with Behcet's disease (BD) and in 107 apparently healthy individuals. The mutation was present in the heterozygous state in 37.5% of the patients with a history of deep vein thrombosis (12/32) and in 9.4% of the patients without any thrombotic event (3/32). Eleven healthy individuals were also heterozygous for the mutation (10.3%). The prevalence of the mutation in BD patients with and without thrombosis was significantly different (P = 0.0079). We conclude that the factor V gene mutation may play a major role in the development of venous thrombosis in BD