Journal of medical genetics
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Silver-Russell syndrome (SRS) is a clinically and genetically heterogeneous condition characterised by severe intrauterine and postnatal growth retardation. Loss of DNA methylation at the telomeric imprinting control region 1 (ICR1) on 11p15 is an important cause of SRS. ⋯ The scoring system emerged as a powerful tool for identifying those patients with both a definite SRS phenotype and carrying an epimutation at 11p15. 53% of the 201 patients initially enrolled fulfilled the criteria for SRS and about 40% of them exhibited an epimutation at the H19-IGF2 locus. Methylation defects were restricted to patients who fulfilled the diagnostic criteria for SRS. Patients carrying epimutations had a more severe phenotype than either the SRS patients with mUPD7 or the idiopathic SRS patients. The majority of patients with methylation abnormalities showed hypomethylation at both the H19 and IGF2 genes. However, we also identified SRS patients where hypomethylation was restricted to either the H19 or the IGF2 gene. Interestingly, we detected epimutations in siblings of normal parents, most likely reflecting germ cell mosaicism in the fathers. In one family, we identified an epimutation in an affected father and his likewise affected daughter.
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Fragile X syndrome (FXS) is the most common single gene inherited form of mental retardation, with behaviours at the extreme of the autistic spectrum. Subjects with FXS and fragile X mental retardation gene knock out (Fmr1 KO) mice, an animal model for FXS, have been shown to exhibit defects in dendritic spine maturation that may underlie cognitive and behavioural abnormalities in FXS. Minocycline is a tetracycline analogue that has been used in clinical trials for stroke, multiple sclerosis and several neurodegenerative conditions. ⋯ These findings establish minocycline as a promising therapeutic for the treatment of fragile X mental retardation.
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Plexiform neurofibromas are benign tumours that occur in more than half of people with neurofibromatosis 1 (NF1). These tumours can cause serious complications and can also progress to malignant peripheral nerve sheath tumours (MPNSTs), one of the leading causes of death among NF1 patients. Plexiform neurofibromas are clinically heterogeneous, and knowledge of their natural history is limited. In order to characterise the growth of plexiform neurofibromas better, we performed serial magnetic resonance imaging (MRI) in NF1 patients with such tumours. ⋯ Longitudinal MRI is a valuable means of monitoring the growth of plexiform neurofibromas in individuals with NF1.
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In order to identify a gene(s) susceptible to idiopathic pulmonary fibrosis (IPF), we conducted a genome-wide association (GWA) study by genotyping 159 patients with IPF and 934 controls for 214 508 tag single-nucleotide polymorphisms (SNPs). We further evaluated selected SNPs in a replication sample set (83 cases and 535 controls) and found a significant association of an SNP in intron 2 of the TERT gene (rs2736100), which encodes a reverse transcriptase that is a component of a telomerase, with IPF; a combination of two data sets revealed a p value of 2.9 x 10(-8) (GWA, 2.8 x 10(-6); replication, 3.6 x 10(-3)). Considering previous reports indicating that rare mutations of TERT are found in patients with familial IPF, we suggest that the common genetic variation within TERT may contribute to the risk of sporadic IFP in the Japanese population.
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Genetic testing for the breast and ovarian cancer susceptibility genes BRCA1 and BRCA2 has important implications for the clinical management of people found to carry a mutation. However, genetic testing is expensive and may be associated with adverse psychosocial effects. To provide a cost-efficient and clinically appropriate genetic counselling service, genetic testing should be targeted at those individuals most likely to carry pathogenic mutations. Several algorithms that predict the likelihood of carrying a BRCA1 or a BRCA2 mutation are currently used in clinical practice to identify such individuals. ⋯ Carrier prediction algorithms provide a rational basis for counselling individuals likely to carry BRCA1 or BRCA2 mutations. Their widespread use would improve equity of access and the cost-effectiveness of genetic testing.