4 patients at Gillette Children's Specialty Healthcare have this deletion.
See: http://dgnews.docguide.com/imaging-links-language-delay-chromosome-deletion-children-neurological-disorders?overlay=2&nl_ref=newsletter&pk_campaign=newsletter
Jenkins J 3rd, Chow V, Blaskey L, Kuschner E, Qasmieh S, Gaetz L, Edgar JC,Mukherjee P, Buckner R, Nagarajan SS, Chung WK, Spiro JE, Sherr EH, Berman JI,Roberts TP. Auditory Evoked M100 Response Latency is Delayed in Children with 16p11.2 Deletion but not 16p11.2 Duplication. Cereb Cortex. 2015 Feb 11. pii:bhv008. [Epub ahead of print] PubMed PMID: 25678630.
Abstract
Individuals with the 16p11.2 BP4-BP5 copy number variant (CNV) exhibit a range of behavioral phenotypes that may include mild impairment in cognition and clinical diagnoses of autism spectrum disorder (ASD). To better understand auditory processing impairments in populations with this chromosomal variation, auditory evoked responses were examined in children with the 16p11.2 deletion, 16p11.2 duplication, and age-matched controls. Stimuli consisted of sinusoidal binaural tones presented passively while children underwent recording with magnetoencephalography (MEG). The primary indicator of auditory processing impairment was the latency of the ∼100-ms "M100" auditory response detected by MEG, with the 16p11.2 deletion population exhibiting profoundly delayed M100 latencies relative to controls. This delay remained even after controlling for potential confounds such as age and cognitive ability. No significant difference in M100 latency was observed between 16p11.2 duplication carriers and controls. Additionally, children meeting diagnostic criteria for ASD (16p11.2 deletion carriers) exhibited nonsignificant latency delays when compared with the corresponding CNV carriers not meeting criteria for ASD. Present results indicate that 16p11.2 deletion is associated with auditory processing delays analogous to (but substantially more pronounced than) those previously reported in "idiopathic" ASD.
More news regarding 16p11.2. http://www.mdlinx.com/neurology/top-medical-news-today-list.cfm/8
Autism genes activate during fetal brain development
February 20, 2015 source: UC San Diego Health System
Scientists at the University of California, San Diego School of Medicine have found that mutations that cause autism in children are connected to a pathway that regulates brain development. The research, led by Lilia Iakoucheva, PhD, assistant professor in the Department of Psychiatry, is published in the February 18 issue of Neuron. The researchers studied a set of well–known autism mutations called copy number variants or CNVs. They investigated when and where the genes were expressed during brain development. “One surprising thing that we immediately observed was that different CNVs seemed to be turned on in different developmental periods,” said Iakoucheva. Specifically, the scientists noted that one CNV located in a region of the genome known as 16p11.2, contained genes active during the late mid–fetal period. Ultimately, they identified a network of genes that showed a similar pattern of activation including KCTD13 within 16p11.2 and CUL3, a gene from a different chromosome that is also mutated in children with autism.
Lin GN, Corominas R, Lemmens I, Yang X, Tavernier J, Hill DE, Vidal M, Sebat J, Iakoucheva LM. Spatiotemporal 16p11.2 Protein Network Implicates Cortical Late Mid-Fetal Brain Development and KCTD13-Cul3-RhoA Pathway in Psychiatric Diseases. Neuron. 2015 Feb 18;85(4):742-754.
Abstract
The psychiatric disorders autism and schizophrenia have a strong genetic component, and copy number variants (CNVs) are firmly implicated. Recurrent deletions and duplications of chromosome 16p11.2 confer a high risk for both diseases, but the pathways disrupted by this CNV are poorly defined. Here we investigate the dynamics of the 16p11.2 network by integrating physical interactions of 16p11.2 proteins with spatiotemporal gene expression from the developing human brain. We observe profound changes in protein interaction networks throughout different stages of brain development and/or in different brain regions. We identify the late mid-fetal period of cortical development as most critical for establishing the connectivity of 16p11.2 proteins with their co-expressed partners. Furthermore, our results suggest that the regulation of the KCTD13-Cul3-RhoA pathway in layer 4 of the inner cortical plate is crucial for controlling brain size and connectivity and that its dysregulation by de novo mutations may be a potential determinant of 16p11.2 CNV deletion and duplication phenotypes
Hala Harony-Nicolas, Silvia De Rubeis, Alexander Kolevzon, and Joseph D. Buxbaum Phelan McDermid Syndrome: From Genetic Discoveries to Animal Models and Treatment J Child Neurol 0883073815600872, first published on September 8, 2015 as doi:10.1177/0883073815600872
ReplyDeleteAbstract
Phelan-McDermid syndrome or 22q13.3 deletion syndrome is a rare neurodevelopmental disorder characterized by generalized developmental delay, intellectual disability, absent or delayed speech, seizures, autism spectrum disorder, neonatal hypotonia, physical dysmorphic features, and recurrent medical comorbidities. Individuals with Phelan-McDermid syndrome have terminal deletions of the chromosomal region 22q13.3 encompassing SHANK3, a gene encoding a structural component of excitatory synapses indispensable for proper synaptogenesis and neuronal physiology, or point mutations within the gene. Here, we review the clinical aspects of the syndrome and the genetic findings shedding light onto the underlying etiology. We also provide an overview on the evidence from genetic studies and mouse models that supports SHANK3 haploinsufficiency as a major contributor of the neurobehavioral manifestations of Phelan-McDermid syndrome. Finally, we discuss how all these discoveries are uncovering the pathophysiology of Phelan-McDermid syndrome and are being translated into clinical trials for novel therapeutics ameliorating the core symptoms of the disorder.