Polygenic risk associations with developmental and mental health outcomes in childhood and adolescence: A systematic review.

Background: Neurodevelopmental and mental health disorders in childhood constitute an emerging global concern, with adverse sequelae which span children's physical, psychological and social well-being. The aetiology of these disorders is likely complex, multifactorial and polygenic. Polygenic risk scores (PRS), an estimate of an individual's genetic liability toward a disorder, have been increasingly used in psychiatric research to explore genetic associations with disorders of interest. However, limited work delineates polygenic associations with development and mental health in childhood populations.We aimed to systematically review existing literature on associations between genetic risk (as measured by PRS) and neurodevelopmental and mental health outcomes in childhood and adolescence. Methods: Following the recommended Preferred Reporting Items for Meta-Analyses (PRISMA) guidelines, databases were searched using key search terms. The search commenced in March 2021 and concluded in June 2021. The studies eligible for inclusion were full-text articles investigating polygenic risk associations with neurodevelopmental and/or mental health outcomes in childhood or adolescence. Results: Fourteen studies were eligible for inclusion in this systematic review. The association between higher PRS for attention-deficit/hyperactivity disorder (ADHD) and adverse developmental/mental health outcomes in childhood and adolescence was reported by five studies. Additionally, associations between PRS for bipolar disorder or major depressive disorder and adverse outcomes of interest were also described by two studies; and two studies highlighted associations between schizophrenia PRS and mental health disorders in childhood. The remaining studies highlighted shared polygenic contributions between and within NDDs and mental health disorders in children. Conclusion: The findings of this systematic review suggest that PRS for neurodevelopmental and mental health disorders may associate with adverse neurodevelopmental and mental health outcomes from early childhood to adolescence. In addition, these associations seemed not to be phenotype-specific, suggesting potential shared genetic variation across the phenotypes of interest.

Does thyroid-sparing total laryngectomy decrease the risk of hypothyroidism?

BACKGROUND: Thyroid lobectomy is recommended with total laryngectomy for laryngeal cancer in the National Comprehensive Cancer Network ('NCCN') guidelines. However, it is associated with a 32-89 per cent risk of hypothyroidism, with or without adjuvant radiotherapy. OBJECTIVE: The study aimed to determine whether preserving the whole thyroid, compared to a single lobe, does indeed significantly lower the incidence of hypothyroidism in the setting of total laryngectomy. METHOD: A retrospective study was conducted at Groote Schuur Hospital in Cape Town, South Africa. RESULTS: Eighty-four patients met the inclusion criteria. The overall incidence of hypothyroidism was 45.2 per cent. The incidence of hypothyroidism was significantly reduced in patients who underwent thyroid-sparing total laryngectomy compared to hemithyroidectomy (p = 0.037). Adjuvant radiotherapy was associated with a higher incidence of hypothyroidism (p = 0.001). CONCLUSION: Thyroid-preserving laryngectomy should be advocated in carefully selected patients with advanced laryngeal carcinoma, as it reduces the incidence of hypothyroidism.

Potential use of clinical polygenic risk scores in psychiatry - ethical implications and communicating high polygenic risk.

Psychiatric disorders present distinct clinical challenges which are partly attributable to their multifactorial aetiology and the absence of laboratory tests that can be used to confirm diagnosis or predict risk. Psychiatric disorders are highly heritable, but also polygenic, with genetic risk conferred by interactions between thousands of variants of small effect that can be summarized in a polygenic risk score. We discuss four areas in which the use of polygenic risk scores in psychiatric research and clinical contexts could have ethical implications. First, there is concern that clinical use of polygenic risk scores may exacerbate existing health inequities. Second, research findings regarding polygenic risk could be misinterpreted in stigmatising or discriminatory ways. Third, there are concerns associated with testing minors as well as eugenics concerns elicited by prenatal polygenic risk testing. Fourth, potential challenges that could arise with the feedback and interpretation of high polygenic risk for a psychiatric disorder would require consideration. While there would be extensive overlap with the challenges of feeding back genetic findings in general, the potential clinical use of polygenic risk scoring warrants discussion in its own right, given the recency of this possibility. To this end, we discuss how lay interpretations of risk and genetic information could intersect. Consideration of these factors would be necessary for ensuring effective and constructive communication and interpretation of polygenic risk information which, in turn, could have implications for the uptake of any therapeutic recommendations. Recent advances in polygenic risk scoring have major implications for its clinical potential, however, care should be taken to ensure that communication of polygenic risk does not feed into problematic assumptions regarding mental disorders or support reductive interpretations.

Polygenic risk for schizophrenia and associated brain structural changes: A systematic review.

BACKGROUND: Genome wide association studies (GWAS) of schizophrenia allow the generation of Polygenic Risk Scores (PRS). PRS can be used to determine the contribution to altered brain structures in this disorder, which have been well described. However, findings from studies using PRS to predict brain structural changes in schizophrenia have been inconsistent. We therefore performed a systematic review to determine the association between schizophrenia PRS and brain structure. METHODS: Following PRISMA systematic review guidelines, databases were searched for literature using key search terms. Inclusion criteria for the discovery sample required case-control schizophrenia GWAS summary statistics from European populations. The target sample was required to be of European ancestry, and have brain structure and genotype information. Quality assessment of the publications was conducted using the Mixed Methods Appraisal Tool for quantitative non-randomised studies. MAIN FINDINGS: A total of seven studies were found to be eligible for review. Five studies found no significant association and two studies found a significant association of schizophrenia PRS with total brain, reduced white matter volume, and globus pallidus volume. However, the latter studies were conducted using smaller discovery (ncases = 9394 ncontrols = 12,462) and target samples compared to the studies with substantially larger discovery (ncases = 33,636 ncontrols = 43,008) and target samples where no association was observed. Taken together, the results suggest that schizophrenia PRS are not significantly associated with brain structural changes in this disorder. CONCLUSIONS: The lack of significant association between schizophrenia PRS and brain structural changes may indicate that intermediate phenotypes other than brain structure should be the focus of future work. Alternatively, however, the lack of association found here may point to limitations of the current evidence-base, and so point to the need for future better powered studies.

Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability.

The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-PTSD) combined genome-wide case-control molecular genetic data across 11 multiethnic studies to quantify PTSD heritability, to examine potential shared genetic risk with schizophrenia, bipolar disorder, and major depressive disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we report a molecular genetics-based heritability estimate (h2SNP) for European-American females of 29% that is similar to h2SNP for schizophrenia and is substantially higher than h2SNP in European-American males (estimate not distinguishable from zero). We found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder. No single-nucleotide polymorphisms (SNPs) exceeded genome-wide significance in the transethnic (overall) meta-analysis and we do not replicate previously reported associations. Still, SNP-level summary statistics made available here afford the best-available molecular genetic index of PTSD-for both European- and African-American individuals-and can be used in polygenic risk prediction and genetic correlation studies of diverse phenotypes. Publication of summary statistics for ∼10 000 African Americans contributes to the broader goal of increased ancestral diversity in genomic data resources. In sum, the results demonstrate genetic influences on the development of PTSD, identify shared genetic risk between PTSD and other psychiatric disorders and highlight the importance of multiethnic/racial samples. As has been the case with schizophrenia and other complex genetic disorders, larger sample sizes are needed to identify specific risk loci.

Promoter region variation in NFE2L2 influences susceptibility to ototoxicity in patients exposed to high cumulative doses of cisplatin.

Ototoxicity is a disabling reaction to cisplatin chemotherapy. Much of the inter-individual variability in the development of hearing impairment among cisplatin-receiving patients has not been fully accounted for. In particular, little is known about the pharmacogenomics of cisplatin-induced ototoxicity. This study sought to investigate the role of variation in five candidate genes in a cohort of South African cancer patients. Five variants within the candidate genes were genotyped in 214 patients, of which SLC22A2 rs316019 and NFE2L2 rs6721961 associated with reduced rates of ototoxicity. In the patients who were exposed to cumulative cisplatin doses ⩾200 mg m-2 (n=113), the variant rs6721961 associated with ototoxicity according to three different grading scales of hearing loss (ASHA, P=0.005; Chang, P=0.028; CTCAE, P=0.004). The NFE2L2 promotor variant rs6721961 may therefore be protective against hearing loss in cisplatin-receiving cancer patients.

High prevalence of cisplatin-induced ototoxicity in Cape Town, South Africa.

BACKGROUND: Cisplatin is administered as the first-line treatment of soft-tissue cancers. It has a reported cure rate of up to 85%, but is associated with a high incidence of ototoxicity, characterised by irreversible bilateral hearing loss and affecting 23 - 50% of adults who receive the drug. OBJECTIVES: To determine the incidence of cisplatin-induced ototoxicity at Groote Schuur Hospital (GSH), Cape Town, South Africa. METHODS: retrospective cross-sectional study of cisplatin-receiving cancer patients attending GSH between January 2006 and August 2011. RESULTS: A total of 377 patients were recorded as receiving cisplatin therapy during the study period. A 300% increase in new cisplatin-receiving patients receiving audiological monitoring was observed between 2006 and 2010. However, only patients with all clinical data as well as baseline and follow-up audiometric analyses were investigated. One hundred and seven such patients were identified, 55.1% of whom developed cisplatin-induced ototoxicity while receiving high-dose (> or = 60 mg/m2) cisplatin treatment. Higher cumulative cisplatin dosages were associated with development of significant hearing loss (p = 0.027). The odds of developing cisplatin-induced hearing loss were elevated for patients with head and neck tumours and lymphoma (p = 0.0465 and p = 0.0563, respectively) and were significantly lower for those with reproductive cancers (p = 0.0371). CONCLUSION: Comprehensive audiological monitoring should be available for every patient during cisplatin treatment to minimise the development of disabling hearing loss.

Psychosis and relapse in bipolar disorder are related to GRM3, DAOA, and GRIN2B genotype.

OBJECTIVE: Dysfunction in glutamate signalling is thought to play a role in the pathophysiology of bipolar disorder (BD). There is evidence of associations between single nucleotide polymorphisms (SNPs) in GRM3, GRIN2B, and DAOA genes and the diagnosis of BD. In this pilot study, we investigated the frequency of SNP variants in these 3 genes within South African population groups, and assessed interactions between genes and phenotypes of BD disease severity. METHOD: Multiplex SNaPshotTM PCR was used to genotype 191 case and 188 control samples. Cases comprised of 191 individuals in a South African cohort of mixed ancestry and Caucasians, with BD Type 1. Phenotypes of BD disease severity were: age of onset, number of illness episodes, number of hospitalisations for depression or mania and history of psychotic symptoms. RESULTS: There were no significant difference in SNP allele frequencies between cases and controls. In the case-only analysis, the GRM3 rs6465084 heterozygote was associated with a 4-fold increased risk of lifetime history of psychotic symptoms, and the specific variants within the gene pair, DAOA and GRIN2B, had a significant interaction with the number of hospitalisations for mania, with lowest admission rates associated with both pairs of ancestral alleles. CONCLUSION: In BD, variations in glutamatergic genes may influence phenotypes related to the severity of illness. Speculatively, newly derived genes associated with various evolutionary advantages, may also increase the risk for more severe BD. These preliminary findings deserve validation in a larger cohort.

Psychosis and relapse in bipolar disorder are related to GRM3, DAOA, and GRIN2B genotype

Objective: Dysfunction in glutamate signalling is thought to play a role in the pathophysiology of bipolar disorder (BD). There is evidence of associations between single nucleotide polymorphisms (SNPs) in GRM3, GRIN2B, and DAOA genes and the diagnosis of BD. In this pilot study, we investigated the frequency of SNP variants in these 3 genes within South African population groups, and assessed interactions between genes and phenotypes of BD disease severity. Method: Multiplex SNaPshotTM PCR was used to genotype 191 case and 188 control samples. Cases comprised of 191 individuals in a South African cohort of mixed ancestry and Caucasians, with BD Type 1. Phenotypes of BD disease severity were: age of onset, number of illness episodes, number of hospitalisations for depression or mania and history of psychotic symptoms. Results: There were no significant difference in SNP allele frequencies between cases and controls. In the case-only analysis; the GRM3 rs6465084 heterozygote was associated with a 4-fold increased risk of lifetime history of psychotic symptoms, and the specific variants within the gene pair, DAOA and GRIN2B, had a significant interaction with the number of hospitalisations for mania, with lowest admission rates associated with both pairs of ancestral alleles. Conclusion: In BD, variations in glutamatergic genes may influence phenotypes related to the severity of illness. Speculatively; newly derived genes associated with various evolutionary advantages, may also increase the risk for more severe BD. These preliminary findings deserve validation in a larger cohort

Mobile thoracolumbar gibbus in Morquio type A: the cause of paraparesis and its management.

Four children with Morquio A syndrome had neurologic deterioration related to a progressive thoracolumbar gibbus. Findings on the magnetic resonance imaging scan did not suggest a significant canal compromise, but X-rays taken in the erect position showed a much larger kyphosis, and thus more canal compromise. All patients recovered neurologically after anterior decompression and correction of kyphosis. We believe that the cause of cord dysfunction is mobility at the kyphus and compression by the bulging discs and the internal gibbus.

Anterior instrumented fusion for thoracolumbar kyphosis in mucopolysaccharidosis.

STUDY DESIGN: A case series of seven children who had a thoracolumbar gibbus related to mucopolysaccharidosis treated with anterior instrumentation were reported retrospectively. OBJECTIVE: To describe a new technique for treating progressive thoracolumbar kyphosis in children with mucopolysaccharidosis. SUMMARY OF BACKGROUND DATA: Management of this condition is not well represented in the literature. Isolated reports on the surgical management of this disorder appear, but there is no previous report of correction performed anteriorly. METHODS: Seven patients underwent anterior instrumentation for correction of a thoracolumbar gibbus not arrested by brace treatment. Preoperative kyphosis ranged from 42 degrees to 64 degrees (average, 52.5 degrees ). Data on all seven patients were collected prospectively. The technique and its principles are described. RESULTS: A good correction of the kyphosis was obtained, with postoperative angles of 3 degrees to 29 degrees (average, 15 degrees ), and maintained through the follow-up period. There were no complications from the procedure. CONCLUSION: Anterior instrumented correction and fusion of the spine is effective in treating thoracolumbar kyphosis associated with mucopolysaccharidosis.

Analytical data of March 1993 blast victims--the KEM Hospital experience.

On 13th March 1993 consequent to a series of explosions in the city a large number of casualties were attended to at this hospital. A total of 248 patients were treated for various injuries which included 85 minor and 34 major operations. Seventy-nine patients were brought in "dead on arrival". There were 12 deaths after admission out of which 6 patients died after surgery. The cause of death was hemorrhagic shock in 5 patients, burns in 2, severe head injury in 2, and shock lung in 3 patients.

Analytical data of January 1993 communal riot victims--the KEM Hospital experience.

Bombay experienced a violent outbreak of communal rioting in January 1993. Four hundred and thirteen casualties were treated in the KEM hospital from January 7 to January 15, of which 194 required admission and further management. Twenty-seven were brought dead on arrival. The large influx of casualties sustained over a period of 9 days tended to overwhelm the medical facilities. The data of the admitted patients are analyzed to identify the frequency of admissions, cause and nature of injuries sustained, management and prognosis of casualties in such a catastrophe. An attempt is also made to identify the problems faced during such a crisis and a few suggestions made for their solution.

Distribution of immobilized enzymes on porous membranes.

In this article, the results from a theoretical and experimental investigation of enzyme immobilization in porous membranes are reported. A theoretical model of the immobilization process, which accounts for restricted diffusion of enzyme in the pores of the membrane, has been developed. The model predicts the effect of immobilization kinetics and time of immobilization on the enzyme distribution in the pores of the membrane. The immobilization of glucose oxidase and glucose oxidase-biotin conjugate on porous alumina membranes was experimentally investigated. Enzyme uptake data was correlated to the theory to determine the rate constant of immobilization and the distribution of the enzyme in the pore. Immobilization studies were carried out for enzyme adsorption and for enzyme attachment by covalent coupling. The distribution of enzyme was experimentally studied by assembling five membranes in the diffusion cell. Following immobilization, the membranes were separated and each was assayed for activity. The amount of active enzyme present in each membrane yielded a discrete distribution that compared well with that predicted by theory.