A 600 kb deletion syndrome at 16p11.2 leads to energy imbalance and neuropsychiatric disorders

BACKGROUND: The recurrent ~600 kb 16p11.2 BP4-BP5 deletion is among the most frequent known genetic aetiologies of autism spectrum disorder (ASD) and related neurodevelopmental disorders. OBJECTIVE: To define the medical, neuropsychological, and behavioural phenotypes in carriers of this deletion. METHODS: We collected clinical data on 285 deletion carriers and performed detailed evaluations on 72 carriers and 68 intrafamilial non-carrier controls. RESULTS: When compared to intrafamilial controls, full scale intelligence quotient (FSIQ) is two standard deviations lower in carriers, and there is no difference between carriers referred for neurodevelopmental disorders and carriers identified through cascade family testing. Verbal IQ (mean 74) is lower than non-verbal IQ (mean 83) and a majority of carriers require speech therapy. Over 80% of individuals exhibit psychiatric disorders including ASD, which is present in 15% of the paediatric carriers. Increase in head circumference (HC) during infancy is similar to the HC and brain growth patterns observed in idiopathic ASD. Obesity, a major comorbidity present in 50% of the carriers by the age of 7 years, does not correlate with FSIQ or any behavioural trait. Seizures are present in 24% of carriers and occur independently of other symptoms. Malformations are infrequently found, confirming only a few of the previously reported associations. CONCLUSIONS: The 16p11.2 deletion impacts in a quantitative and independent manner FSIQ, behaviour and body mass index, possibly through direct influences on neural circuitry. Although non-specific, these features are clinically significant and reproducible. Lastly, this study demonstrates the necessity of studying large patient cohorts ascertained through multiple methods to characterise the clinical consequences of rare variants involved in common diseases.

Differentiating hippocampal subregions by means of quantitative magnetization transfer and relaxometry: preliminary results

The hippocampal formation (HF) of healthy control subjects and schizophrenic patients was examined using an MRI experiment that implements sequences for relaxometry and magnetization transfer (MT) quantification. In addition to the semi-quantitative magnetization transfer ratio (MTR), all of the observable properties of the binary spin bath model were included. The study demonstrates that, in contrast to the MTR, quantitative MT parameters (especially the T2 relaxation time of restricted protons, T2b) are capable to differentiate functionally significant subregions within the HF. The MT methodology appears to be a promising new tool for the differential microstructural evaluation of the HF in neuropsychiatric disorders accompanied by memory disturbances.

Disease Caused by Mutations in NaV-β Subunit Genes

NaV-b subunits associate with the NaV-a or pore-forming subunit of the voltage-dependent sodium channel and play critical roles in channel expression, voltage dependence of the channel gating, cell adhesion, signal transduction, and channel pharmacology. Five NaV-b subunits have been identified in humans, all of them implicated in many primary arrhythmia syndromes that cause sudden death or neurologic disorders, including long QT syndrome, Brugada syndrome, cardiac conduction disorders, idiopathic ventricular fibrillation, epilepsy, neurodegenerative diseases, and neuropsychiatric disorders.

Examining carer stress in dementia: the role of subtype diagnosis and neuropsychiatric symptoms

INTRODUCTION: Caring for people with dementia incurs significant stress for carers. Stress has been related to the duration of caring role, the number of weekly hours provided and severity of cognitive impairment. What remains less clear is the impact of neuropsychiatric symptoms and subtype of dementia on carer stress and this study aimed to examine these. METHODS: Dementia carers were recruited for people with a range of dementia subtypes. Carers were interviewed using the Neuropsychiatric Inventory with the Carer Distress Scale. Cognitive fluctuations were assessed using the Dementia Cognitive Fluctuations Scale. All patients were also examined with The Cambridge Assessment for mental disorders in the elderly. RESULTS: Dementia diagnostic subtype, the presence of cognitive fluctuations and some neuropsychiatric symptoms (psychosis and mood disturbance) did predict carer stress (all at p < 0.01) but age, gender and severity of cognitive impairment did not (all p > 0.33). Carers of people with dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) experienced more stress than those caring for patients with Alzheimer's disease and vascular dementia. Carer stress was associated with higher levels of psychosis, mood disturbances, daytime sleep and cognitive fluctuations in the person with dementia. CONCLUSIONS: This study identified the significant impact on carers of providing care for people with DLB and PDD dementia subtypes and also highlighted the significant impact of providing care for patients with high levels of psychosis, mood disturbances and cognitive fluctuations.