Lymphoblast transcriptome analysis in 22q11.2 deletion syndrome individuals with schizophrenia-spectrum disorder

Objectives: 22q11.2 deletion is the most prominent risk factor for schizophrenia (SZ). The aim of the present study was to identify unique transcriptome profile for 22q11.2 deletion syndrome (DS)-related SZ spectrum disorder (SZ-SD).Methods: We performed RNA-Seq screening in lymphoblasts collected from 20 individuals with 22q11.2DS (10 men and 10 women, 4 of each sex with SZ-SD and 6 with no psychotic disorders (Np)).Results: Sex effect in RNA-Seq descriptive analysis led to separating the analyses between men and women. In women, only one differentially expressed gene (DEG), HLA-DQA2, was associated with SZ-SD. In men, 48 DEGs (adjp < 0.05) were found to be associated with SZ-SD. Ingenuity pathway analysis of top 85 DEGs (p < 4.66E-04) indicated significant enrichment for immune-inflammatory response (IIR) and neuro-inflammatory signaling pathways. Additionally, NFATC2, IFNG, IFN-alpha, STAT1 and IL-4 were identified as upstream regulators. Co-expression network analysis revealed the contribution of endoplasmic reticulum protein processing and N-Glycan biosynthesis. These findings indicate dysregulation of IIR and post-translational protein modification processes in individuals with 22q11.2DS-related SZ-SD.Conclusions: Candidate pathways and upstream regulators may serve as novel biomarkers and treatment targets for SZ. Future transcriptome studies, including larger samples and proteomic analysis, are needed to substantiate our findings.

Use of multiple polygenic risk scores for distinguishing schizophrenia-spectrum disorder and affective psychosis categories in a first-episode sample; the EU-GEI study

BACKGROUND

Schizophrenia (SZ), bipolar disorder (BD) and depression (D) run in families. This susceptibility is partly due to hundreds or thousands of common genetic variants, each conferring a fractional risk. The cumulative effects of the associated variants can be summarised as a polygenic risk score (PRS). Using data from the EUropean Network of national schizophrenia networks studying Gene-Environment Interactions (EU-GEI) first episode case-control study, we aimed to test whether PRSs for three major psychiatric disorders (SZ, BD, D) and for intelligent quotient (IQ) as a neurodevelopmental proxy, can discriminate affective psychosis (AP) from schizophrenia-spectrum disorder (SSD).

METHODS

Participants (842 cases, 1284 controls) from 16 European EU-GEI sites were successfully genotyped following standard quality control procedures. The sample was stratified based on genomic ancestry and analyses were done only on the subsample representing the European population (573 cases, 1005 controls). Using PRS for SZ, BD, D, and IQ built from the latest available summary statistics, we performed simple or multinomial logistic regression models adjusted for 10 principal components for the different clinical comparisons.

RESULTS

In case-control comparisons PRS-SZ, PRS-BD and PRS-D distributed differentially across psychotic subcategories. In case-case comparisons, both PRS-SZ [odds ratio (OR) = 0.7, 95% confidence interval (CI) 0.54-0.92] and PRS-D (OR = 1.31, 95% CI 1.06-1.61) differentiated AP from SSD; and within AP categories, only PRS-SZ differentiated BD from psychotic depression (OR = 2.14, 95% CI 1.23-3.74).

CONCLUSIONS

Combining PRS for severe psychiatric disorders in prediction models for psychosis phenotypes can increase discriminative ability and improve our understanding of these phenotypes. Our results point towards the potential usefulness of PRSs in specific populations such as high-risk or early psychosis phases.

Schizophrenia spectrum disorders in Denmark between 2000 and 2018: Incidence and early diagnostic transition

BACKGROUND

Schizophrenia spectrum disorders (SSD) comprise a group of related mental disorders, which share clinical features and common genetic disposition, but it is unknown if there is a diagnostic transition between these disorders over time. We aimed to study the incidence at the first SSD diagnosis between 2000 and 2018, defined as schizophrenia, schizotypal or schizoaffective disorder, and the early diagnostic transition between these disorders.

METHODS

Using Danish nationwide healthcare registers, we identified all individuals aged 15-64 years during the period from 2000 to 2018 in Denmark and calculated the yearly incidence rates for the specific SSDs. We studied the diagnostic pathways from the first ever diagnosis of an SSD across the subsequent two treatment courses with an SSD diagnosis to evaluate early diagnostic stability, and explore potential changes over time.

RESULTS

Among 21,538 patients, yearly incidence rates per 10,000 individuals were similar during the observation period for schizophrenia (2000: 1.8; 2018: 1.6), lower for schizoaffective disorder (2000: 0.3; 2018: 0.1) and increasing for schizotypal disorder (2000: 0.7; 2018: 1.3). Among the subgroup of 13,417 individuals with three separate treatment courses, early diagnostic stability was present among 89.9% which differed between the disorders (schizophrenia: 95.4%; schizotypal disorder: 78.0%; schizoaffective disorder: 80.5%). Among 1352 (10.1%) experiencing an early diagnostic transition, 398 (3.0%) were diagnosed with schizotypal disorder after a schizophrenia or schizoaffective disorder diagnosis.

CONCLUSION

This study provides comprehensive incidence rates for SSDs. The majority of patients experienced early diagnostic stability, but sizable proportions of people with initial schizophrenia or schizoaffective disorder are subsequently diagnosed with schizotypal disorder.

Cognitive function in early-phase schizophrenia-spectrum disorder: IQ subtypes, brain volume and immune markers

BACKGROUND

Evidence suggests that cognitive subtypes exist in schizophrenia that may reflect different neurobiological trajectories. We aimed to identify whether IQ-derived cognitive subtypes are present in early-phase schizophrenia-spectrum disorder and examine their relationship with brain structure and markers of neuroinflammation.

METHOD

161 patients with recent-onset schizophrenia spectrum disorder (<5 years) were recruited. Estimated premorbid and current IQ were calculated using the Wechsler Test of Adult Reading and a 4-subtest WAIS-III. Cognitive subtypes were identified with k-means clustering. Freesurfer was used to analyse 3.0 T MRI. Blood samples were analysed for hs-CRP, IL-1RA, IL-6 and TNF-α.

RESULTS

Three subtypes were identified indicating preserved (PIQ), deteriorated (DIQ) and compromised (CIQ) IQ. Absolute total brain volume was significantly smaller in CIQ compared to PIQ and DIQ, and intracranial volume was smaller in CIQ than PIQ (F(2, 124) = 6.407, p = 0.002) indicative of premorbid smaller brain size in the CIQ group. CIQ had higher levels of hs-CRP than PIQ (F(2, 131) = 5.01, p = 0.008). PIQ showed differentially impaired processing speed and verbal learning compared to IQ-matched healthy controls.

CONCLUSIONS

The findings add validity of a neurodevelopmental subtype of schizophrenia identified by comparing estimated premorbid and current IQ and characterised by smaller premorbid brain volume and higher measures of low-grade inflammation (CRP).

Health-related quality of life in adolescents and young adults with high functioning autism-spectrum disorder

AIM

Over the last years, health-related quality of life (HRQOL) has emerged as an important measure not only in somatic medicine but also in psychiatry. To date, there are only few reports on HRQOL in patients with autism-spectrum disorder (ASD). This study aimed at studying HRQOL in ASD patients with an IQ >70, using a self-report HRQOL questionnaire with cross-cultural validity.

METHODS

In this cross-sectional study, twenty-six male adolescents and young adults with the diagnosis of Asperger Syndrome, high functioning autism and atypical autism were evaluated, using the German version of the WHOQOL-BREF HRQOL questionnaire.

RESULTS

Mean WHOQOL-BREF global scores were 60.6 (SD ±26.1), mean WHOQOL-BREF subscale scores were 70.1 (SD ±19.1) for the domain "physical health", 61.5 (SD ±21.9) for the domain "psychological health", 53.8 (SD ±23.5) for the domain "social relationships" and 67.9 (SD ±17.4) for the domain "environment". Compared to a reference population of healthy controls, our sample scored significantly lower in three of four WHOQOL-BREF domains. In comparison to a reference sample of individuals with schizophrenia spectrum disorder (SSD), HRQOL of our sample was significantly better in all domains except for the "social relations" domain. There was a significant association between HRQOL and the Vineland Adaptive Behavior Scales domain "daily living skills", but not with age, IQ, or ADOS-G summary scores.

CONCLUSION

Overall self-reported HRQOL in patients with high functioning ASD seems to be lower than in healthy individuals, but better than in patients with SSD. Also, higher HRQOL was associated with better daily living skills. This interrelationship should especially be accounted for in the design and application of treatment programmes for individuals with ASD, as it is of importance for the level of self-perceived HRQOL.