Genome-wide analysis of rare copy number variations reveals PARK2 as a candidate gene for attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a common, highly heritable neurodevelopmental disorder. Genetic loci have not yet been identified by genome-wide association studies. Rare copy number variations (CNVs), such as chromosomal deletions or duplications, have been implicated in ADHD and other neurodevelopmental disorders. To identify rare (frequency ≤1%) CNVs that increase the risk of ADHD, we performed a whole-genome CNV analysis based on 489 young ADHD patients and 1285 adult population-based controls and identified one significantly associated CNV region. In tests for a global burden of large (>500 kb) rare CNVs, we observed a nonsignificant (P=0.271) 1.126-fold enriched rate of subjects carrying at least one such CNV in the group of ADHD cases. Locus-specific tests of association were used to assess if there were more rare CNVs in cases compared with controls. Detected CNVs, which were significantly enriched in the ADHD group, were validated by quantitative (q)PCR. Findings were replicated in an independent sample of 386 young patients with ADHD and 781 young population-based healthy controls. We identified rare CNVs within the parkinson protein 2 gene (PARK2) with a significantly higher prevalence in ADHD patients than in controls (P=2.8 × 10(-4) after empirical correction for genome-wide testing). In total, the PARK2 locus (chr 6: 162 659 756-162 767 019) harboured three deletions and nine duplications in the ADHD patients and two deletions and two duplications in the controls. By qPCR analysis, we validated 11 of the 12 CNVs in ADHD patients (P=1.2 × 10(-3) after empirical correction for genome-wide testing). In the replication sample, CNVs at the PARK2 locus were found in four additional ADHD patients and one additional control (P=4.3 × 10(-2)). Our results suggest that copy number variants at the PARK2 locus contribute to the genetic susceptibility of ADHD. Mutations and CNVs in PARK2 are known to be associated with Parkinson disease.

Analyses of non-synonymous obesity risk alleles in SH2B1 (rs7498665) and APOB48R (rs180743) in obese children and adolescents undergoing a 1-year lifestyle intervention

Association of obesity risk alleles of single nucleotide polymorphisms (SNPs) near or in the SH2B adaptor protein 1 gene (SH2B1) and increased body mass index (BMI) has been often described. A gene in close proximity, apolipoprotein B48 receptor gene (APOB48R), is tagged by the same SNP(s).We analyzed 454 overweight and obese children and adolescents (10.8±2.6 years, BMI-SDS 2.4±0.5; 55% girls) who completed a 1-year lifestyle intervention ('Obeldicks' program). Carriers of obesity risk alleles of non-synonymous SNPs in SH2B1 (rs7498665, Thr484Ala) or APOB48R (rs180743, Pro419Ala), as genotyped by TaqMan, were analysed for changes in anthropometrics (body-mass index (BMI), and standardized BMI (BMI-SDS)), blood pressure (systolic and diastolic) and plasma parameters (total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerides, glucose, insulin, and HOMA).We observed no evidence for an association of the obesity risk alleles to alterations in any of the analyzed phenotypes. Both mean BMI and BMI-SDS improved during the intervention independent of genotype. The mean systolic blood pressure was lowered and concentrations of HDL-cholesterol increased significantly.The obesity risk alleles of non-synonymous SNPs at SH2B1 and APOB48R have no strong effect on weight loss-related phenotypes in overweight children after a 1-year lifestyle intervention.

Prognostic significance of chromosome 3 alterations determined by microsatellite analysis in uveal melanoma: a long-term follow-up study

BACKGROUND

In uveal melanoma (UM), the most frequent primary intraocular tumour in adults, loss of one entire chromosome 3 (monosomy 3 (M3)) is observed in ~50% of tumours and is significantly associated with metastatic disease. The strong association of metastatic disease with M3 offers the opportunity for molecular prognostic testing of UM patients.

METHODS

To re-evaluate M3 as prognostic marker in our clinical and laboratory setting and to determine the metastatic potential of rare tumours with partial M3, we performed a comprehensive study on 374 UM patients treated by enucleation in our clinic within 10 consecutive years, starting in 1998. Genotyping of all tumours was performed by microsatellite analysis.

RESULTS

Median follow-up time was 5.2 years. The disease-specific mortality rates (death by UM metastases) for tumours with disomy 3 (D3) and M3 were 13.2% and 75.1%, respectively. The disease-specific survival was worse when M3 was observed together with chromosome 8 alterations (P=0.020). Death of UM metastases was also observed in 12 patients (9%) with D3 tumours. The metastasising D3 tumours showed a larger basal tumour diameter (P=0.007), and were more frequently of mixed or epitheloid cell type (P<0.0001) than D3 tumours that did not metastasise. Mortality rate of tumours showing partial M3 (8.3%) was as low as that for tumours with D3.

CONCLUSION

This shows that large tumours with disomy 3 have an increased risk to develop metastases. On the basis of these results, our clinic offers routine prognostic testing of UM patients by chromosome 3 typing.

The fatty acid amide hydrolase (FAAH) gene variant rs324420 AA/AC is not associated with weight loss in a 1-year lifestyle intervention for obese children and adolescents

Adult obese carriers of the A allele of SNP rs324420 in the fatty acid amide hydrolase (FAAH) gene lose more weight and improve associated phenotypes better than non-carriers during an intervention. We aimed to replicate this finding in obese children and adolescents undergoing a one year lifestyle intervention (Obeldicks program). A total of 453 overweight and obese children and adolescents (10.8±2.6 years, BMI-SDS 2.4±0.5; 55% girls) were genotyped for rs324420 (C/A) by restriction fragment length polymorphism (RFLP) analysis. Participants were prescribed a balanced diet, containing 55 En% carbohydrates, 30 En% fat, and 15 En% proteins. Moreover, they took part in an exercise therapy once a week. Blood was taken at baseline and after 1 year of intervention. Anthropometric (height, weight, BMI, and BMI-SDS) and plasma parameters (total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerides, glucose, insulin, and HOMA) as well as blood pressure were measured. Both mean BMI and BMI-SDS improved significantly. The mean systolic blood pressure was also lowered and concentrations of HDL-cholesterol increased significantly. However, none of the measured changes were associated with FAAH rs324420 AA/AC genotype. We did not detect evidence for an association of FAAH genotypes with weight reduction in overweight and obese children and adolescents. Hence, the previous finding in adults could not be confirmed. As the length (1 year as compared to 3 months) and mode of treatment (hypocaloric diet in adults vs. physical activity plus balanced meals) of the interventions varied, these parameters might have influenced the inconsistent results.

Impact of immunosuppressive therapy on hepatitis C infection after renal transplantation

BACKGROUND

Among patients after renal transplantation (NTx), hepatitis C virus (HCV) infection is a risk factor for graft loss and patient death caused by hepatic decompensation. Also, HCV has been implicated in the pathogenesis of glomerular diseases in native and transplanted kidneys. Therefore, the aim of this retrospective cohort study was to determine the effects of the widely used calcineurin inhibitors (CNI) cyclosporine A (CsA) and tacrolimus (Tac) on hepatitis C virus replication, inflammatory activity, development of liver fibrosis, and long-term renal graft function.

SUBJECTS AND METHODS

A cohort of 71 patients with HCV infection after kidney transplantation under immunosuppression with either CsA or Tac were analyzed for viral kinetics and serum transaminases. In addition, presence of liver fibrosis was detected by non-invasive measurements using the FibroScan. Graft function was determined biochemically. Patients with interferon therapy prior to transplantation were excluded from the study in order to avoid any impact of the antiviral therapy on outcomes.

RESULTS

In the early period after transplantation, hepatitis C viral load was lower in patients treated with Tac as compared to CsA. This effect became negligible 3 months after transplantation. However, hepatic inflammatory activity was reduced in the CsA-treated group. Extent of liver fibrosis was similar in both groups of HCV-infected patients as well as in a control group of non-HCV-infected patients after renal transplantation (NTx), respectively. Renal function and glomerular filtration rate, as calculated by the modification of diet in renal disease (MDRD) formula, were significantly better in patients treated with Tac.

CONCLUSIONS

During long-term immunosuppression, the CNIs cyclosporine A versus tacrolimus showed no significant differences in HCV-infected patients after renal transplantation with respect to viral replication and development of liver fibrosis. However, function of the renal graft is significantly better preserved in patients receiving tacrolimus.