Molecular Genetic Studies of Early-Onset Schizophrenia

Childhood-Onset Schizophrenia: A Systematic Overview of Its Genetic Heterogeneity From Classical Studies to the Genomic Era

“…In total, 32 candidate genes have been described on 12 autosomes (1, 2, 3, 6, 7, 8, 11, 13, 15, 17, 19, and 22) and 1 sex chromosome (X) (Tables 1 and 2) through the following studies (Addington et al, 2004;Sekizawa et al, 2004;Gornick et al, 2005;Addington et al, 2005;Addington et al, 2007;Pakhomova et al, 2010;Addington et al, 2011;Raznahan et al, 2011;Smedemark-Margulies et al, 2016;Chaumette et al, 2018;Ambalavanan et al, 2019):…”

“…Further, several novel four-marker haplotypes are associated with COS (lowest p = 0.0004). b. Population-Based "Case vs. Control" Studies (From 2004 to 2011) A polymorphism (VAL66MET) in the BDNF (11p13) gene was associated with COS in a 65 patient cohort (10.5 ± 3.7 years old at onset) vs. 111 controls (p = 0.03; χ² test) (Pakhomova et al, 2010). A mutation (VAL158MET) in COMT (22q11.21) that increases protein activity levels in the brain accelerated adolescent cortical thinning (MRI findings) in both schizophrenia probands and their siblings (with resolution after a certain age for siblings), illustrating the influence of dopaminergic disruption on brain cortical maturation.…”

Strong family history and early onset of schizophrenia: about 2 families in Northern Nigeria

“…Studies have reported that early-onset schizophrenia, defined by manifestation of psychotic symptoms before 18 years of age, occurs in 4% of all schizophrenia cases [ 1 ]. It has also been shown that this early onset cases are familial variant of the adult-onset schizophrenia with strong genetic liability [ 2 ]. Because early-onset cases show clinical, cognitive, genetic and neurobiologic continuity with adult-onset schizophrenia but with enduring clinical morbidity and psychosocial disability [ 3 ], it is necessary to identify families with early onset disease.…”

Association of the T102C polymorphism in the HTR2A gene with major depressive disorder, bipolar disorder, and schizophrenia

“…Although the association between the T102C polymorphism and MDD, BPD, and SCZ has been explored in many studies, the findings are inconsistent. Some studies have suggested that the T102C polymorphism is associated with susceptibility to MDD [Du et al, ; Li et al, ] and SCZ [Erdmann et al, ; Baritaki et al, ]; however, a number of studies failed to provide evidence to support these associations [Illi et al, ; Yosifova et al, ; Pakhomova et al, ]. As far as we know, a meta‐analysis confirming an association between the T102C polymorphism and MDD has not been published to date, and the meta‐analysis conducted by Seifuddin [] to investigate the T102C polymorphism and BPD did not give a definitive conclusion.…”