Familial Variability of Disease Severity in Adult Patients With ADPKD.

Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic nephropathy and has striking familial variability of disease severity. Methods: To better comprehend familial phenotypic variability, we analyzed clinical and pedigree data on 92 unrelated ADPKD kindreds with ≥2 affected individuals (N = 292) from an Irish population. All probands underwent genetic sequencing. Age at onset of kidney failure (KF), decline in estimated glomerular filtration rate (eGFR), predicting renal outcome in polycystic kidney disease (PROPKD) score, and imaging criteria were used to assess and grade disease severity as mild, intermediate, or severe. One mild and 1 severe case per family defined marked intrafamilial variability of disease severity. Results: Marked intrafamilial variability was observed in at least 13% of the 92 families, with a higher proportion of families carrying PKD1-nontruncating (PKD1-NT) variants. In families with ≥2 members affected by KF, the average intrafamilial age difference was 7 years, and there was no observed difference in intrafamilial variability of age at KF between allelic groups. The prespecified criteria showed marked familial variability in 7.7%, 8.4%, and 24% for age at KF, the PROPKD score, and imaging criteria, respectively. In our multivariate mixed-effects model, the intrafamilial variability in kidney survival was independent of the measured genotypic factors associated with prognosis and survival (P = <0.001). Conclusion: Using objective measures, we quantified marked intrafamilial variability in ADPKD disease phenotype in at least 13% of families. Our findings indicate that intrafamilial phenotypic variability remains incompletely understood and necessitates a more thorough identification of relevant clinical and genotypic factors.

Rare disease gene association discovery from burden analysis of the 100,000 Genomes Project data.

To discover rare disease-gene associations, we developed a gene burden analytical framework and applied it to rare, protein-coding variants from whole genome sequencing of 35,008 cases with rare diseases and their family members recruited to the 100,000 Genomes Project (100KGP). Following in silico triaging of the results, 88 novel associations were identified including 38 with existing experimental evidence. We have published the confirmation of one of these associations, hereditary ataxia with UCHL1 , and independent confirmatory evidence has recently been published for four more. We highlight a further seven compelling associations: hypertrophic cardiomyopathy with DYSF and SLC4A3 where both genes show high/specific heart expression and existing associations to skeletal dystrophies or short QT syndrome respectively; monogenic diabetes with UNC13A with a known role in the regulation of ß cells and a mouse model with impaired glucose tolerance; epilepsy with KCNQ1 where a mouse model shows seizures and the existing long QT syndrome association may be linked; early onset Parkinson's disease with RYR1 with existing links to tremor pathophysiology and a mouse model with neurological phenotypes; anterior segment ocular abnormalities associated with POMK showing expression in corneal cells and with a zebrafish model with developmental ocular abnormalities; and cystic kidney disease with COL4A3 showing high renal expression and prior evidence for a digenic or modifying role in renal disease. Confirmation of all 88 associations would lead to potential diagnoses in 456 molecularly undiagnosed cases within the 100KGP, as well as other rare disease patients worldwide, highlighting the clinical impact of a large-scale statistical approach to rare disease gene discovery.

Oxytocin and vasopressin genes are significantly associated with schizophrenia in a large Arab-Israeli pedigree.

We have previously studied the genetics of schizophrenia in a large inbred Arab-Israeli pedigree and found evidence for linkage on chromosome 20p13. This locus harbours four strong candidate genes for schizophrenia: atractin (ATRN), pantonate-kinase2 (PANK2), oxytocin (OXT) and arginine-vasopressin (AVP). In this study we further explored the association of these genes with schizophrenia in the pedigree and searched for the disease-causing variants. A mutation screening of affected individuals from the pedigree was performed by using intensive sequencing in these four genes of interest. Then, we studied the prevalence of the identified variants in all family members (n=56) as well as in Arab-Israeli nuclear families (n=276) and a Jewish case-control sample (n=545). We also studied the possible functional role of these variants by examining their association with gene expression in the brain (n=104). We identified seven genetic variants in the OXT-AVP cluster in affected individuals from the pedigree. Three of these variants were significantly associated with schizophrenia in this pedigree. A 7-SNP haplotype was also significantly associated with disease. We found significant association of some of these variants in the two samples from the general population. Expression data analysis showed a possible functional role of two of these variants in regulation of gene expression. Involvement of OXT and AVP in the aetiology of schizophrenia has been suggested in the past. This study demonstrates, for the first time, a significant genetic association of these neuropeptides with schizophrenia and strongly supports this hypothesis.

Optimizing prediction of response to antidepressant medications using machine learning and integrated genetic, clinical, and demographic data.

Major depressive disorder (MDD) is complex and multifactorial, posing a major challenge of tailoring the optimal medication for each patient. Current practice for MDD treatment mainly relies on trial and error, with an estimated 42-53% response rates for antidepressant use. Here, we sought to generate an accurate predictor of response to a panel of antidepressants and optimize treatment selection using a data-driven approach analyzing combinations of genetic, clinical, and demographic factors. We analyzed the response patterns of patients to three antidepressant medications in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, and employed state-of-the-art machine learning (ML) tools to generate a predictive algorithm. To validate our results, we assessed the algorithm's capacity to predict individualized antidepressant responses on a separate set of 530 patients in STAR*D, consisting of 271 patients in a validation set and 259 patients in the final test set. This assessment yielded an average balanced accuracy rate of 72.3% (SD 8.1) and 70.1% (SD 6.8) across the different medications in the validation and test set, respectively (p < 0.01 for all models). To further validate our design scheme, we obtained data from the Pharmacogenomic Research Network Antidepressant Medication Pharmacogenomic Study (PGRN-AMPS) of patients treated with citalopram, and applied the algorithm's citalopram model. This external validation yielded highly similar results for STAR*D and PGRN-AMPS test sets, with a balanced accuracy of 60.5% and 61.3%, respectively (both p's < 0.01). These findings support the feasibility of using ML algorithms applied to large datasets with genetic, clinical, and demographic features to improve accuracy in antidepressant prescription.

The transcription factor CUX1 negatively regulates invasion in castrate resistant prostate cancer.

Metastatic prostate cancer is treated with androgen ablation therapy but progress to castrate resistant prostate cancer (CRPC). This study aimed to investigate the role of CUX1 in CRPC using clinical samples and in vitro models. CUX1 expression was increased in androgen-independent cells compared to androgen-sensitive cells. The multi-isoform nature of CUX1 makes it difficult to assay in tissue microarrays as there is no epitope able to distinguish the many isoforms for immunohistochemistry. Using surrogate markers, we found no differential expression between castrate resistant and local hormone naïve tissue. However, differences have been demonstrated at the transcript level. In androgen-sensitive cells, migration, but not invasion, increased following CUX1 knockdown. Conversely, in androgen-independent cells, invasion was increased. This observed difference in invasion capacity is not E-cadherin mediated, as CUX1 knockdown increases the expression of E-cadherin in both cell lines with no inter-cell line difference. Cells expressed different ratios of p110/p200 isoforms depending on androgen status and cathepsin L was only detectable in androgen-sensitive cells. MMP3 is upregulated in the androgen-independent cells. Rather than a simple presence or absence of CUX1, the relative balance of CUX1 isoforms and their interplay may be a significant factor in the functional role of CUX1 in CRPC.

Genome-wide linkage scan, fine mapping, and haplotype analysis in a large, inbred, Arab Israeli pedigree suggest a schizophrenia susceptibility locus on chromosome 20p13.

Linkage and association studies in schizophrenia have repeatedly drawn attention to several chromosomal regions and to genes within them. Conflicting patterns of association and the lack of a clear functional significance of the associated variants limit the interpretation of these results. The use of rare pedigrees, where genes with a major effect cause the disorder, has been proven beneficial in studies of other complex disorders. Our objective was to use this advantage by performing a genome wide linkage analysis for schizophrenia in a large, multiplex Israeli Arab pedigree. We genotyped 346 microsatellite markers in 24 pedigree members affected with schizophrenia spectrum disorders and 32 unaffected relatives. Two-point linkage analysis with SUPERLINK demonstrated a LOD score of 2.47 for D20S116 on chromosome 20p13 under an autosomal dominant mode of inheritance. Further fine mapping yielded a two-point LOD score of 2.56 for the adjacent marker D20S193 and narrowed down the linked region to 2-5 cM. A haplotype containing the markers D20S193, D20S889, and D20S116, 0.7 Mb in length, was found to be shared by most affected pedigree members. Genotyping of 43 SNPs in the interval supported these results with a multipoint LOD score of 2.7 around D20S193. We were also able to better define the boundaries of the shared haplotype which contains strong candidate genes for schizophrenia. Our study exemplifies the power of rare and unique pedigrees in drawing attention to novel regions for genetic studies of schizophrenia.

Survival in acute myeloid leukemia is associated with NKp44 splice variants.

NKp44 is a receptor encoded by the NCR2 gene, which is expressed by cytokine-activated natural killer (NK) cells that are involved in anti-AML immunity. NKp44 has three splice variants corresponding to NKp44ITIM+ (NKp44-1) and NKp44ITIM- (NKp44-2, and NKp44-3) isoforms. RNAseq data of AML patients revealed similar survival of NKp46+NKp44+ and NKp46+NKp44- patients. However, if grouped according to the NKp44 splice variant profile, NKp44-1 expression was significantly associated with poor survival of AML patients. Moreover, activation of PBMC from healthy controls showed co-dominant expression of NKp44-1 and NKp44-3, while primary NK clones show more diverse NKp44 splice variant profiles. Cultured primary NK cells resulted in NKp44-1 dominance and impaired function associated with PCNA over-expression by target cells. This impaired functional phenotype could be rescued by blocking of NKp44 receptor. Human NK cell lines revealed co-dominant expression of NKp44-1 and NKp44-3 and showed a functional phenotype that was not inhibited by PCNA over-expression. Furthermore, transfection-based overexpression of NKp44-1, but not NKp44-2/NKp44-3, reversed the endogenous resistance of NK-92 cells to PCNA-mediated inhibition, and resulted in poor formation of stable lytic immune synapses. This research contributes to the understanding of AML prognosis by shedding new light on the functional implications of differential splicing of NKp44.

NKp44 and NKp30 splice variant profiles in decidua and tumor tissues: a comparative viewpoint.

NKp44 and NKp30 splice variant profiles have been shown to promote diverse cellular functions. Moreover, microenvironment factors such as TGF-ß, IL-15 and IL-18 are able to influence both NKp44 and NKp30 splice variant profiles, leading to cytokine-associated profiles. Placenta and cancerous tissues have many similarities; both are immunologically privileged sites and both share immune tolerance mechanisms to support tissue development. Therefore, we studied the profiles of NKp44 and NKp30 splice variants in these states by comparing (i) decidua from pregnancy disorder and healthy gestation and (ii) matched normal and cancer tissue. Decidua samples had high incidence of both NKp44 and NKp30. In cancerous state it was different; while NKp30 expression was evident in most cancerous and matched normal tissues, NKp44 incidence was lower and was mostly associated with the cancerous tissues. A NKp44-1dominant inhibitory profile predominated in healthy pregnancy gestation. Interestingly, the NKp44-2/3 activation profile becomes the leading profile in spontaneous abortions, whereas balanced NKp44 profiles were observed in preeclampsia. In contrast, a clear preference for the NKp30a/b profile was evident in the 1st trimester decidua, yet no significant differences were observed for NKp30 profiles between healthy gestation and spontaneous abortions/preeclampsia. Both cancerous and matched normal tissues manifested balanced NKp30c inhibitory and NKp30a/b activation profiles with a NKp44-1dominant profile. However, a shift in NKp30 profiles between matched normal and cancer tissue was observed in half of the cases. To summarize, NKp44 and NKp30 splice variants profiles are tissue/condition specific and demonstrate similarity between placenta and cancerous tissues.

Extracting tumor tissue immune status from expression profiles: correlating renal cancer prognosis with tumor-associated immunome.

Investigating the expression of genes in cancer-associated immune cells (immunome) is imperative for prognosis prediction. However, evaluating the expression of immune-associated genes within cancer biopsy is subject to significant inconsistencies related to the sampling methodology. Here, we present immFocus, a method for extracting immune signals from total RNA sequencing of tumor biopsies, intended for immunity depiction and prognosis evaluation. It is based on reducing the variation which biopsy preparation adds to the apparent expression levels of immune genes. We employed immFocus to normalize gene expression with an immune index using data obtained from renal clear cell carcinoma biopsies. Genes that became less variable due to normalization were found to be preferentially immune-related. Moreover, immune-related genes tended to become more prognostic due to the normalization. These results demonstrate, for the first time, that whole transcriptome sequencing can be used for interrogation of a cancer immunome and for advancing immune-based prognosis.

Severe methylenetetrahydrofolate reductase deficiency: clinical clues to a potentially treatable cause of adult-onset hereditary spastic paraplegia.

IMPORTANCE: Hereditary spastic paraplegia is a highly heterogeneous group of neurogenetic disorders with pure and complicated clinical phenotypes. No treatment is available for these disorders. We identified 2 unrelated families, each with 2 siblings with severe methylenetetrahydrofolate reductase (MTHFR) deficiency manifesting a complicated form of adult-onset hereditary spastic paraparesis partially responsive to betaine therapy. OBSERVATIONS: Both pairs of siblings presented with a similar combination of progressive spastic paraparesis and polyneuropathy, variably associated with behavioral changes, cognitive impairment, psychosis, seizures, and leukoencephalopathy, beginning between the ages of 29 and 50 years. By the time of diagnosis a decade later, 3 patients were ambulatory and 1 was bedridden. Investigations have revealed severe hyperhomocysteinemia and hypomethioninemia, reduced fibroblast MTHFR enzymatic activity (18%-52% of control participants), and 3 novel pathogenic MTHFR mutations, 2 as compound heterozygotes in one family and 1 as a homozygous mutation in the other family. Treatment with betaine produced a rapid decline of homocysteine by 50% to 70% in all 4 patients and, over 9 to 15 years, improved the conditions of the 3 ambulatory patients. CONCLUSIONS AND RELEVANCE: Although severe MTHFR deficiency is a rare cause of complicated spastic paraparesis in adults, it should be considered in select patients because of the potential therapeutic benefit of betaine supplementation.

Involvement of PTPN5, the gene encoding the striatal-enriched protein tyrosine phosphatase, in schizophrenia and cognition.

OBJECTIVE: Striatal-enriched protein tyrosine phosphatase (STEP) is a brain-specific member of the protein tyrosine phosphatase (PTP) family that has been implicated in learning and memory. In this study, we examined the association of the protein tyrosine phosphatase non-receptor 5 (PTPN5) gene, which encodes for STEP, with both schizophrenia and cognitive functioning in the Israeli Jewish population. METHODS: A schizophrenia (SZ) case-control study of 868 participants was carried out (286 patients and 582 controls). Eleven PTPN5 tagging single-nucleotide polymorphisms (SNPs) were selected and single markers and haplotype association analyses were carried out. A cognitive variability study included 437 healthy women who completed a computerized cognitive battery. We performed univariate associations between the SNPs and cognitive performance. The possible functional role of these variants was examined by studying their association with gene expression levels in the brain. RESULTS: In the SZ study, we found a nominal association in the whole sample between rs4075664 and SZ. Male patients with SZ showed a more significant association for three SNPs (rs4075664, rs2278732, and rs4757710). Haplotypes of the studied SNPs were associated with SZ both in the overall sample and within the male subsample. Expression analysis provided some support for the effects of the associated SNPs on PTPN5 expression level. The cognitive variability study showed positive associations between PTPN5 SNPs and different cognitive subtests. Principal component analysis showed an 'attention index' neurocognitive component that was associated with two SNP pairs (rs10832983 × rs10766504 and rs7932938 × rs4757718). CONCLUSION: The results imply a model in which PTPN5 may play a role in normal cognitive functioning and contribute to aspects of the neuropathology of SZ.

Selected summaries from the XVII World Congress of Psychiatric Genetics, San Diego, California, USA, 4-8 November 2009.

The XVII World Congress of Psychiatric Genetics, sponsored by The International Society of Psychiatric Genetics (ISPG) took place in San Diego, California from 4 to 8 November 2009. Approximately 550 participants gathered to discuss the latest molecular genetic findings relevant to serious mental illness, including schizophrenia, mood disorders, substance abuse, autism, and attention deficit disorder. Recent advances in the field were discussed, including the genome-wide association studies results, copy number variation (CNV) in the genome, genomic imaging, and large multicenter collaborations. The following report, written by junior travel awardees who were assigned sessions as rapporteurs represents some of the areas covered in oral presentation during the conference, and reports on some of the notable major new findings described at this 2009 World Congress of Psychiatric Genetics.