Dosage-sensitive X-linked locus influences the development of amygdala and orbitofrontal cortex, and fear recognition in humans.

Détails

ID Serval
serval:BIB_087C78A284F7
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Dosage-sensitive X-linked locus influences the development of amygdala and orbitofrontal cortex, and fear recognition in humans.
Périodique
Brain
Auteur(s)
Good C.D., Lawrence K., Thomas N.S., Price C.J., Ashburner J., Friston K.J., Frackowiak R.S., Oreland L., Skuse D.H.
ISSN
0006-8950 (Print)
ISSN-L
0006-8950
Statut éditorial
Publié
Date de publication
2003
Volume
126
Numéro
Pt 11
Pages
2431-2446
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Résumé
The amygdala, which plays a critical role in emotional learning and social cognition, is structurally and functionally sexually dimorphic in humans. We used magnetic neuroimaging and molecular genetic analyses with healthy subjects and patients possessing X-chromosome anomalies to find dosage-sensitive genes that might influence amygdala development. If such X-linked genes lacked a homologue on the Y-chromosome they would be expressed in one copy in normal 46,XY males and two copies in normal 46,XX females. We showed by means of magnetic neuroimaging that 46,XY males possess significantly increased amygdala volumes relative to normal 46,XX females. However, females with Turner syndrome (45,X) have even larger amygdalae than 46,XY males. This finding implies that haploinsufficiency for one or more X-linked genes influences amygdala development irrespective of a direct or indirect (endocrinological) mechanism involving the Y-chromosome. 45,X females also have increased grey matter volume in the orbitofrontal cortex bilaterally, close to a region implicated in emotional learning. They are as poor as patients with bilateral amygdalectomies in the recognition of fear from facial expressions. We attempted to localize the gene(s) responsible for these deficits in X-monosomy by means of a deletion mapping strategy. We studied female patients possessing structural X-anomalies of the short arm. A genetic locus (no greater than 4.96 Mb in size) at Xp11.3 appears to play a key role in amygdala and orbitofrontal structural and (by implication) functional development. Females with partial X-chromosome deletions, in whom this critical locus is deleted, have normal intelligence. Their fear recognition is as poor as that of 45,X females and their amygdalae are correspondingly enlarged. This 4.96 Mb region contains, among others, the genes for monoamine oxidase A (MAOA) and B (MAOB), which are involved in the oxidative deamination of several neurotransmitters, including dopamine and serotonin. Abnormal activity of these neurotransmitters has been implicated in the aetiology of several neurodevelopmental disorders in which social cognitive deficits are prominent. These associated deficits include a specific lack of fear recognition from facial expressions. We show that the thrombocytic activity of MAOB is proportionate to the number of X-chromosomes, and hypothesize that haploinsufficiency of this enzyme in 45,X females predisposes to their deficits in social cognition.
Mots-clé
Adolescent, Adult, Amygdala/growth & development, Child, Chromosome Mapping/methods, Chromosomes, Human, X/genetics, Facial Expression, Fear, Female, Frontal Lobe/growth & development, Gene Deletion, Gene Dosage, Genetic Diseases, X-Linked/genetics, Genetic Diseases, X-Linked/physiopathology, Humans, Intelligence, Karyotyping, Magnetic Resonance Imaging/methods, Male, Middle Aged, Neuropsychological Tests, Pattern Recognition, Visual, Turner Syndrome/genetics, Turner Syndrome/physiopathology
Pubmed
Web of science
Création de la notice
11/09/2011 19:39
Dernière modification de la notice
03/03/2018 13:30
Données d'usage