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J T Epplen

Publications and source records attributed to J T Epplen.

At least 37 records · Page 2Linked to original sources
PubMed2005

A case-control study of tyrosine phosphatase (PTPN22) confirms the lack of association with Crohn's disease.

In Crohn's disease (CD), the whole gastrointestinal tract can be affected by discontinuous and transmural inflammation. The terminal ileum and colon are especially prone to inflammation that comprises granulomata and later intestinal and perianal fistulas. Genome-wide linkage and epidemiological studies established genetic predisposition factors to CD. Recently, a variation of the intracellular protein tyrosine phosphatase nonreceptor-type 22 (PTPN22) was associated with several autoimmune diseases. Here, we analysed the functionally relevant polymorphism R620W (rs 2476601) of the PTPN22 gene in 146 patients suffering from CD using restriction fragment length polymorphism (RFLP) analyses. This study revealed evidence that PTPN22 variation may have no influence in the genetic predisposition to CD, at least not in another well-characterized Caucasian cohort.

Amino Acid Substitution↗
PubMed2004

Methyltetrahydrofolate reductase polymorphism influences onset of Huntington's disease.

Onset of Huntington's disease (HD) negatively correlates with CAG repeat length of the HD gene, which encodes the protein huntingtin. This protein interacts with the homocysteine metabolizing enzyme cystathionine betasynthase (CBS). Objective of this study was to analyze the impact of CAG repeats, polymorphisms of various homocysteine metabolizing enzymes, like CBS, Methyltetrahydrofolate Reductase (MTHTR), Methionine Synthase Reductase (MSR) and methionine synthase (MS) on HD onset in 171 patients. The significant impact of CAG repeats on HD onset (chi2= 25.54, FG = 4, p<0.0001) with a significant correlation between both (R= -0.521, p=0.01) was obvious. HD patients with the homozygous MTHFR-1298-CC significantly (p = 0.024) earlier experienced HD symptoms. There was no influence demonstrable of CBS, MSR and MS. Determination of MTHFR polymorphisms and CAG repeats enables screening for subjects with putative early HD onset in order to study neuroprotective compounds in their efficacy to delay HD symptoms.

Adult↗
PubMed2004

Intergenomic consensus in multifactorial inheritance loci: the case of multiple sclerosis.

Genetic linkage and association studies define chromosomal regions, quantitative trait loci (QTLs), which influence the phenotype of polygenic diseases. Here, we describe a global approach to determine intergenomic consensus of those regions in order to fine map QTLs and select particularly promising candidate genes for disease susceptibility or other polygenic traits. Exemplarily, human multiple sclerosis (MS) susceptibility regions were compared for sequence similarity with mouse and rat QTLs in its animal model experimental allergic encephalomyelitis (EAE). The number of intergenomic MS/EAE consensus genes (295) is significantly higher than expected if the animal model was unrelated to the human disease. Hence, this approach contributes to the empirical evaluation of animal models for their applicability to the study of human diseases.

Animals↗
PubMed2004

A rare form of narcolepsy (HLA-DR2-) shows possible association with (functionally relevant) alpha-interferon gene polymorphisms.

Narcolepsy is a neuropsychiatric disease caused by complex disturbance of sleep regulation. The main symptoms comprise daytime sleepiness and cataplexy. Although the aetiology remains unclear so far, narcolepsy is genetically characterized by strong linkage to the human leukocyte antigen complex as more than 90% of the patients are typed HLA-DR2+. Recently, it has become apparent that the orexin (hypocretin) neurotransmitter system plays a key role in the pathogenesis of the disease. Canine narcolepsy is caused by mutations in the orexin receptor 2 gene, and narcoleptic patients show specifically decreased cerebrospinal fluid orexin levels. Decreased promotor activity of the prepro-orexin gene is caused by binding of alpha-interferon in vitro. To investigate the possible role of IFNA gene polymorphisms in the pathogenesis of narcolepsy, we have genotyped two single nucleotide polymorphisms in IFNA genes as well as a neighbouring microsatellite. No association was evident in the prevalent DR2+ group. Yet, the IFNA10 single nucleotide polymorphisms and the IFNA microsatellite are associated with the DR2- patient group. Thus, the pathogenetic role of interferons needs to be defined in DR2- narcolepsy.

Carrier Proteins↗
PubMed2004

Spinocerebellar ataxia type 2 with glial cell cytoplasmic inclusions.

Glial cell cytoplasmic inclusions were identified in a case of spinocerebellar ataxia type 2. These have not been reported before. The inclusions were found in low frequency in the dentate nucleus, cerebellar white matter, pontine transverse fibres, and the inferior olivary nucleus. They were of variable size and shape and expressed ubiquitin, thus resembling glial cytoplasmic inclusions in multiple system atrophy. However, their immunohistochemical profile was different as they did not show immunoreactivity for either tau protein or alpha-synuclein. There was no evidence of expanded polyglutamine tracts in these inclusions, which also failed to label with silver stains. As in many other neurodegenerative diseases, in spinocerebellar ataxia type 2 there may be pathogenic contributions of glial cells other than the common astrogliotic response to neuronal damage.

Adolescent↗
PubMed2004

Apolipoprotein E genotypes do not influence the age of onset in Huntington's disease.

OBJECTIVE: The epsilon4 allele of the apolipoprotein E (ApoE) gene has been defined as a critical factor for early onset neurodegeneration in Pick's, Parkinson's, and Alzheimer's disease. Unexpectedly, the epsilon4 allele appeared to delay the age of onset in Huntington's disease (HD) patients. Furthermore, sex specific effects were reported on earlier age of onset due to the ApoE epsilon2epsilon3 genotype in males with HD. The age of onset of HD is known to be negatively correlated with increasing lengths of pathogenetic CAG expansions in the huntingtin gene. METHODS: In order to examine the effects of CAG block lengths, we have correlated ApoE genotypes with the age of onset in 145 patients symptomatic for HD with psychiatric and somatic symptoms (depression, psychosis, dementia, choreic, and other movement disorders) harbouring only modestly expanded huntingtin alleles (41-45 CAGs). RESULTS: The negative correlation between age of onset and CAG block length was established in our HD cohort. Statistically significant effects of the epsilon4 allele were not obvious regarding clinical characteristics including age of onset, nor were any sex differences for the epsilon2epsilon3 genotype observed. CONCLUSION: The ApoE genotype does not affect the course of HD significantly.

Adult↗