Crosstalk between histone modifications and DNA methylation in patients with intellectual disability due to JARID1C mutations

CCMG Oral Abstract Presentations – Commonwealth A: A01The X-linked gene, JARID1C, encodes a H3K4 demethylase. Mutations in this gene cause intellectual disability (ID). We hypothesized that JARID1C mutations would dysregulate DNA methylation at specific genomic targets ...postprintThe 34th Annual Scientific Meeting of the Canadian College of Medical Geneticists (CCMG 2010), Halifax, NS., 21-23 October 2010. In Abstract Book of the 34th CCMG, 2010, p.

Alpha thalassaemia-mental retardation, X linked

X-linked alpha thalassaemia mental retardation (ATR-X) syndrome in males is associated with profound developmental delay, facial dysmorphism, genital abnormalities and alpha thalassaemia. Female carriers are usually physically and intellectually normal. So far, 168 patients have been reported. Language is usually very limited. Seizures occur in about one third of the cases. While many patients are affectionate with their caregivers, some exhibit autistic-like behaviour. Patients present with facial hypotonia and a characteristic mouth. Genital abnormalities are observed in 80% of children and range from undescended testes to ambiguous genitalia. Alpha-thalassaemia is not always present. This syndrome is X-linked recessive and results from mutations in the ATRX gene. This gene encodes the widely expressed ATRX protein. ATRX mutations cause diverse changes in the pattern of DNA methylation at heterochromatic loci but it is not yet known whether this is responsible for the clinical phenotype. The diagnosis can be established by detection of alpha thalassaemia, identification of ATRX gene mutations, ATRX protein studies and X-inactivation studies. Genetic counselling can be offered to families. Management is multidisciplinary: young children must be carefully monitored for gastro-oesophageal reflux as it may cause death. A number of individuals with ATR-X are fit and well in their 30s and 40s

X-Linked Genes and Risk of Orofacial Clefts: Evidence from Two Population-Based Studies in Scandinavia

Background: Orofacial clefts are common birth defects of complex etiology, with an excess of males among babies with cleft lip and palate, and an excess of females among those with cleft palate only. Although genes on the X chromosome have been implicated in clefting, there has been no association analysis of X-linked markers. Methodology/Principal Findings: We added new functionalities in the HAPLIN statistical software to enable association analysis of X-linked markers and an exploration of various causal scenarios relevant to orofacial clefts. Genotypes for 48 SNPs in 18 candidate genes on the X chromosome were analyzed in two population-based samples from Scandinavia (562 Norwegian and 235 Danish case-parent triads). For haplotype analysis, we used a sliding-window approach and assessed isolated cleft lip with or without cleft palate (iCL/P) separately from isolated cleft palate only (iCPO). We tested three statistical models in HAPLIN, allowing for: i) the same relative risk in males and females, ii) sex-specific relative risks, and iii) X-inactivation in females. We found weak but consistent associations with the oral-facial-digital syndrome 1 (OFD1) gene (formerly known as CXORF5) in the Danish iCL/P samples across all models, but not in the Norwegian iCL/P samples. In sex-specific analyses, the association with OFD1 was in male cases only. No analyses showed associations with iCPO in either the Norwegian or the Danish sample. Conclusions: The association of OFD1 with iCL/P is plausible given the biological relevance of this gene. However, the lack of replication in the Norwegian samples highlights the need to verify these preliminary findings in other large datasets. More generally, the novel analytic methods presented here are widely applicable to investigations of the role of X-linked genes in complex traits

HUMAN GLUCOSE-6-PHOSPHATE-DEHYDROGENASE GENE CARRIED ON A YEAST ARTIFICIAL CHROMOSOME ENCODES ACTIVE ENZYME IN MONKEY CELLS

Yeast artificial chromosomes (YACs) permit the cloning of large tracts of human DNA. A YAC containing the human glucose-6-phosphate dehydrogenase gene is shown to encode active enzyme, supporting the inference that the YAC conserves the structure of the genomic DNA

Crosstalk between histone modification and DNA methylation in patients with intellectual disability syndrome due to JARID1C mutations

The 1st Canadian Conference on Epigenetics (Eh! 2011), London, ON., Canada, 4-7 May 2011

Role of epigenetic dysregulation in neurodevelopmental syndromes: lessons from KDM5C mutations

Poster Session - Epigenetics: program no. 762T: abstract no. 10741Genes encoding proteins that function in epigenetic modification play an important role in normal neurodevelopment. However, the molecular mechanisms that underpin hierarchical epigenetic marks and drive normal development are not well understood. Human diseases caused by mutations in genes that modify epigenetic marks provide a uni...link_to_OA_fulltex