Autor(es):
C. Conceição, Inês 
; Correia, Catarina ; Oliveira, Bárbara ; Duque, Frederico ; Mouga, Susana ; Oliveira, Guiomar ; M. Vicente, Astrid
Data: 2011
Identificador Persistente: http://hdl.handle.net/10400.18/400
Origem: Repositório Científico do Instituto Nacional de Saúde
Assunto(s): Perturbações do Desenvolvimento Infantil e Saúde Mental
Descrição
Autism Spectrum Disorders (ASD) have a strong genetic component, with an estimated heritability of over 90%. Recent studies carried out by the Autism Genome Project (AGP) consortium suggest that rare Copy Number Variants (CNV), characterized by submicroscopic chromosomal deletions and duplications, are more frequent in ASD compared to controls, and may play an important role in susceptibility to this disorder. However, to adequately assess pathogenicity, a detailed characterization of patients CNVs is required.
We have been characterizing potentially pathogenic rare CNVs identified by the AGP whole genome CNV analysis of 1,275 ASD individuals. CNV validation in patients and parents and characterization were performed by qPCR and Long-range PCR.
One autistic patient showed a rare deletion absent in 4964 controls of European ancestry with no psychiatric disease history. This deletion was located at 10q22, and encompassed 14 genes, including ANXA7, ZMYND17, PPP3CB and CAMK2G. We validated this CNV as de novo, and accurate breakpoint determination showed that it is smaller than predicted by CNV identification algorithms, including only part of CAMK2G. We found that a 39 nucleotide addition occurred with the deletion, a mutational mechanism previously observed in other CNVs. Expression analysis of ANXA7, ZMYND17 and PPP3CB in this patient, in comparison with controls, is ongoing.
Previous studies identified a genetic association of the ANXA7, PPP3CB and ZMYND17 region with schizophrenia, and significant expression alterations in schizophrenic patients. ANXA7 encodes Annexin7, involved in membrane fusion; interestingly, CNVs in other Annexin genes (ANXA1) have been found in ASD. PPP3CB plays an important role in synaptic plasticity, learning and memory. ZMYND17 has no known function. Our results suggest that alterations in these genes may be risk factors co-observed in autism and schizophrenia. Additional genetic and functional studies may lead to a better understanding of the common pathways between these neuropsychiatric disorders.
