Major impact of the App-Runx1 region in a mouse model of partial monosomy 21

Authors
Thomas Arbogast, Matthieu Raveau, Claire Chevalier, Valérie Nalesso, Doulaye Dembele, Hugues Jacobs, Olivia Wendling, Michel Roux, Arnaud Duchon, Yann Herault

Lab
Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France

Journal
Disease Models and Mechanisms

Abstract
Partial monosomy 21 (PM21) is a rare chromosomal abnormality that is characterized by the loss of a variable segment along human chromosome 21 (Hsa21). Its clinical phenotypes are heterogeneous and range from mild alterations to lethal consequences, depending on the affected region of the Hsa21. The most common features include intellectual disabilities, craniofacial dysmorphology, short stature, and muscular and cardiac defects. As a complement to human genetic approaches, our team has developed new monosomic mouse models that carry deletions on Hsa21 syntenic regions to identify the dosage-sensitive genes responsible for the symptoms. We focused here on the Ms5Yah mouse model, in which a 7.7 Mb region was deleted from the App to Runx1 genes. Ms5Yah mice displayed high postnatal lethality, with a few surviving individuals showing growth retardation, motor coordination deficits and spatial learning and memory impairments. Further studies confirmed a gene dosage effect in the Ms5Yah hippocampus and pinpoint disruptions of pathways related to cell adhesion (App, Cntnap5b, Lgals3bp, Mag, Mcam, Npnt, Pcdhb2/3/4/6/7/8/16 and Vwf). Our PM21 mouse model is the first to display morphological abnormalities and behavioural phenotypes similar to those found in patients, and it therefore demonstrates the major contribution of the App-Runx1 region to the pathophysiology of PM21.

BIOSEB Instruments Used:
Grip strength test (BIO-GS3)