A Rare Novel Deletion of the Tyrosine Hydroxylase Gene in Parkinson Disease

Tyrosine hydroxylase (TH) enzyme is a rate limiting enzyme in dopamine biosynthesis. Missense mutation in both alleles of the TH gene is known to cause dopamine-related phenotypes, including dystonia and infantile Parkinsonism. However, it is not clear if single allele mutation in TH modifies the susceptibility to the adult form of Parkinson disease (PD). We reported a novel deletion of entire TH gene in an adult with PD. The deletion was first identified by copy number variation (CNV) analysis in a genome-wide association study using Illumina Infinium BeadChips. After screening 635 cases and 642 controls, the deletion was found in one PD case but not in any control. The deletion was confirmed by multiple quantitative PCR (qPCR) assays. There is no additional exonic single nucleotide variant in the one copy of TH gene of the patient. The patient has an age-at-onset of 54 years, no evidence for dystonia, and was responsive to L-DOPA. This case supports the importance of the TH gene in PD pathogenesis and raises more attention to rare variants in candidate genes being a risk factor for Parkinson disease. © 2010 Wiley-Liss, Inc

Conventional and Molecular Cytogenetic Analyses in Turkish Patients with Multiple Myeloma

OBJECTIVE: Multiple myeloma (MM) is characterized by the accumulation and proliferation of malignant plasma cells, secreting monoclonal immunoglobulins and genetic abnormalities in MM have implications for disease progression and survival. In the present study, we investigated the frequency of chromosomal abnormalities (CA) in Turkish patients with MM, using interphase FISH and CC and evaluated the relationship between the rearrangements detected, prognosis and stage of disease. METHODS: We performed conventional cytogenetic and FISH studies in 50 patients to detect chromosome anomalies associated with MM. FISH probes were used to detect 13q14, 13q34, 17p13 deletions, IGH rearrangements, and monosomy and/or trisomy of chromosomes 5, 9, and 15. RESULTS: CC studies could be performed in 32 of 50 cases and five patients (15.6%) showed chromosomal aberrations while 27 (84.3%) had normal karyotypes. By FISH, eighteen percent (9/50) of cases were found to be normal for all parameters evaluated. Eighty-two percent (41/50) of the patients were positive for at least one abnormality. Chromosome 13 anomalies were detected in 54% (27/50) of cases. The second most common aberration observed is chromosome 15 aberrations (50%). CONCLUSION: Median survival rate was shorter in patients with one of the abnormalities including chromosome 13 aberrations, IGH rearrangements or P53 deletions. Chromosome 15 aberrations were significantly higher in patients with stage III disease (p=0.02). We conclude that FISH studies should be performed in conjunction with conventional cytogenetic analysis for prognosis in multiple myeloma patients

C9ORF72

We set out to determine whether expansions in the C9ORF72 repeat found in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) families are associated with Parkinson disease (PD). We determined the repeat size in a total of 889 clinically ascertained patients (including PD and essential tremor plus Parkinsonism (ETP)) and 1144 controls using a repeat-primed PCR assay. We found that large C9ORF72 repeat expansions (>30 repeats) were not contributing to PD risk. However, PD and ETP cases had a significant increase in intermediate (>20 to 30+) repeat copies compared to controls. Overall, 14 cases (13 PD, 1 ETP) and three controls had >20 repeat copies (Fisher's exact test p = 0.002). Further, seven cases and no controls had >23 repeat copies (p = 0.003). Our results suggest that intermediate copy numbers of the C9ORF72 repeat contribute to risk for PD and ETP. This also suggests that PD, ALS and FTD share some pathophysiological mechanisms of disease. Further studies are needed to elucidate the contribution of the C9ORF72 repeat in the overall PD population and to determine whether other common genetic risk factors exist between these neurodegenerative disorders

C9ORF72 intermediate repeat copies are a significant risk factor for Parkinson disease.

We set out to determine whether expansions in the C9ORF72 repeat found in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) families are associated with Parkinson disease (PD). We determined the repeat size in a total of 889 clinically ascertained patients (including PD and essential tremor plus Parkinsonism (ETP)) and 1144 controls using a repeat-primed PCR assay. We found that large C9ORF72 repeat expansions (>30 repeats) were not contributing to PD risk. However, PD and ETP cases had a significant increase in intermediate (>20 to 30+) repeat copies compared to controls. Overall, 14 cases (13 PD, 1 ETP) and three controls had >20 repeat copies (Fisher's exact test p = 0.002). Further, seven cases and no controls had >23 repeat copies (p = 0.003). Our results suggest that intermediate copy numbers of the C9ORF72 repeat contribute to risk for PD and ETP. This also suggests that PD, ALS and FTD share some pathophysiological mechanisms of disease. Further studies are needed to elucidate the contribution of the C9ORF72 repeat in the overall PD population and to determine whether other common genetic risk factors exist between these neurodegenerative disorders