Monoamine oxidase B gene variants associated with attention deficit hyperactivity disorder in the Indo-Caucasoid population from West Bengal

Association of Attention Deficit/Hyperactivity Disorder With Events Occurring During Pregnancy and Perinatal Period

Background: The relationship of events occurring during pregnancy and perinatal period with attention deficit/hyperactivity disorder (ADHD) is not clear. Thus, the focus of the current study was to examine the effects of events occurring during pregnancy and perinatal period on ADHD.

Methods: A two-phase cross-sectional study was performed across 13 schools in Changsha and Yiyang cities from March to December, 2014. We preliminarily screened all students using CBCL and established the diagnosis using Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). A total of 3,418 questionnaires were effectively completed in this study.

Results: History of threatened abortion (TA) [odds ratio (OR): 1.707 (1.201–2.426)] (vs. No-TA) and neonatal asphyxia (NA) [OR: 2.497(1.225–5.09)] (vs. health) showed a positive association with ADHD. On subgroup analysis, TA [OR: 2.216 (1.458–3.369)] (vs. No-TA) was a risk factor for ADHD without comorbidity; instrumental delivery [OR: 2.748 (1.057–7.142)] (vs. natural birth) and NA [OR: 2.789 (1.222–6.361)] (vs. health) were risk factors for ADHD in the subgroup of ADHD with comorbidity; TA (vs. no-TA) and NA (vs. health) were risk factors for ADHD among male students [ORs: 2.232 (1.439–3.462) and 2.808 (1.115–7.068), respectively], while low birth weight (LBW) (vs. normal birth weight) was a risk factor [OR: 2.054 (1.063–3.967)] for ADHD among female students.

Conclusion: TA was a risk factor for ADHD in the absence of comorbid conditions; instrumental delivery and NA were risk factors for ADHD in the subgroup of ADHD with comorbidity; TA and NA were risk factors for ADHD among male students. LBW was a risk factor for ADHD among female students.

From aggression to autism: new perspectives on the behavioral sequelae of monoamine oxidase deficiency

The two monoamine oxidase (MAO) enzymes, A and B, catalyze the metabolism of monoamine neurotransmitters, such as serotonin, norepinephrine, and dopamine. The phenotypic outcomes of MAO congenital deficiency have been studied in humans and animal models, to explore the role of these enzymes in behavioral regulation. The clinical condition caused by MAOA deficiency, Brunner syndrome, was first described as a disorder characterized by overt antisocial and aggressive conduct. Building on this discovery, subsequent studies were focused on the characterization of the role of MAOA in the neurobiology of antisocial conduct. MAO A knockout mice were found to display high levels of intermale aggression; however, further analyses of these mutants unveiled additional behavioral abnormalities mimicking the core symptoms of autism-spectrum disorder. These findings were strikingly confirmed in newly reported cases of Brunner syndrome. The role of MAOB in behavioral regulation remains less well-understood, even though Maob-deficient mice have been found to exhibit greater behavioral disinhibition and risk-taking responses, supporting previous clinical studies showing associations between low MAO B activity and impulsivity. Furthermore, lack of MAOB was found to exacerbate the severity of psychopathological deficits induced by concurrent MAOA deficiency. Here, we summarize how the convergence of clinical reports and behavioral phenotyping in mutant mice has helped frame a complex picture of psychopathological features in MAO-deficient individuals, which encompass a broad spectrum of neurodevelopmental problems. This emerging knowledge poses novel conceptual challenges towards the identification of the endophenotypes shared by autism-spectrum disorder, antisocial behavior and impulse-control problems, as well as their monoaminergic underpinnings.

Sex chromosome abnormalities and psychiatric diseases

Excesses of sex chromosome abnormalities in patients with psychiatric diseases have recently been observed. It remains unclear whether sex chromosome abnormalities are related to sex differences in some psychiatric diseases. While studies showed evidence of susceptibility loci over many sex chromosomal regions related to various mental diseases, others demonstrated that the sex chromosome aneuploidies may be the key to exploring the pathogenesis of psychiatric disease. In this review, we will outline the current evidence on the interaction of sex chromosome abnormalities with schizophrenia, autism, ADHD and mood disorders.

ADHD research in India: A narrative review

INTRODUCTION

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with no clear etiopathogenesis. Owing to unique socio cultural milieu of India, it is worthwhile reviewing research on ADHD from India and comparing findings with global research. Thereby, we attempted to provide a comprehensive overview of research on ADHD from India.

METHODS

A boolean search of articles published in English from September 1966 to January 2017 on electronic search engines Google Scholar, PubMed, IndMED, MedIND, using the search terms "ADHD", "Attention Deficit and Hyperactivity Disorder", "Hyperactivity" ,"Child psychiatry", "Hyperkinetic disorder", "Attention Deficit Disorder", "India"was carried out and peer - reviewed studies conducted among human subjects in India were included for review. Case reports, animal studies, previous reviews were excluded from the current review.

RESULTS

Results of 73 studies found eligible for the review were organized into broad themes such as epidemiology, etiology, course and follow up, clinical profile and comorbidity, assessment /biomarkers, intervention/treatment parameters, pathways to care and knowledge and attitude towards ADHD.

DISCUSSION

There was a gap noted in research from India in the domains of biomarkers, course and follow up and non-pharmacological intervention. The prevalence of ADHD as well as comorbidity of Bipolar Disorder was comparatively lower compared to western studies. The studies found unique to India include comparing the effect of allopathic intervention with Ayurvedic intervention, yoga as a non pharmacological intervention. There is a need for studies from India on biomarkers, studies with prospective research design, larger sample size and with matched controls.

Pilot study indicate role of preferentially transmitted monoamine oxidase gene variants in behavioral problems of male ADHD probands

Background

Attention deficit hyperactivity disorder (ADHD) is an etiologically complex childhood onset neurobehavioral disorder characterized by age-inappropriate inattention, hyperactivity, and impulsivity. Symptom severity varies widely and boys are diagnosed more frequently than girls. ADHD probands were reported to have abnormal transmissions of dopamine, serotonin, and/or noradrenaline. Monoamine oxidase A (MAOA) and B (MAOB), mitochondrial outer membrane bound two isoenzymes, mediate degradation of these neurotransmitters and thus regulating their circulating levels. Case-control analyses in different populations, including Indians, suggested involvement of MAOA and MAOB genes in the etiology of ADHD. Due to high heritability rate of ADHD, we tested familial transmission of MAOA and MAOB variants to ADHD probands in 190 nuclear families having ADHD probands from Indo-Caucasoid ethnicity.

Methods

Subjects were recruited following the Diagnostic and Statistical Manual of Mental Disorders-4th edition (DSM-IV). Appropriate scales were used for measuring the behavioral traits in probands. Genotyping was performed through PCR-based amplification of target sites followed by DNA-sequencing and/or gel-electrophoresis. Data obtained were analyzed by family based statistical methods.

Results

Out of 58 variants present in the analyzed sites only 15 were found to be polymorphic (30 bp-uVNTR, rs5906883, rs1465107, rs1465108, rs5905809, rs5906957, rs6323, rs1137070 from MAOA and rs4824562, rs56220155, rs2283728, rs2283727, rs3027441, rs6324, rs3027440 from MAOB). Statistically significant maternal transmission of alleles to male probands was observed for MAOA rs5905809 ‘G’ (p = 0.04), rs5906957 ‘A’ (p = 0.04), rs6323 ‘G’ (p = 0.0001) and MAOB rs56220155 ‘A’ (p = 0.002), rs2283728 ‘C’ (p = 0.0008), rs2283727 ‘C’ (p = 0.0008), rs3027441 ‘T’ (p = 0.003), rs6324 ‘C’ (p = 0.003), rs3027440 ‘T’ (p = 0.0002). Significantly preferential maternal transmissions of different haplotype combinations to male probands were also noticed (p < 0.05), while female probands did not reveal such transmission bias. Behavioral traits of male probands exhibited significant association with gene variants. Age of the mother at pregnancy also revealed association with risk variants of male probands.

Conclusions

It may be inferred that the MAOA and MAOB variants may contribute to the etiology of ADHD in the Indo-Caucasoid population and could be responsible for higher occurrence of ADHD in the boys.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0469-5) contains supplementary material, which is available to authorized users.