Novel ACTG2 variants disclose allelic heterogeneity and bi-allelic inheritance in pediatric chronic intestinal pseudo-obstruction.
Ivana Matera, Domenico Bordo, Marco Di Duca, Margherita Lerone, Giuseppe Santamaria, Marta Pongiglione, Antonella Lezo, Antonella Diamanti, Maria Immacolata Spagnuolo, Alessio Pini Prato, Daniele Alberti, Girolamo Mattioli, Paolo Gandullia, Isabella Ceccherini
Author Information
Ivana Matera: UOSD Genetica e Genomica delle Malattie Rare, IRCCS Istituto Giannina Gaslini, Genoa, Italia, Italy.
Domenico Bordo: IRCCS Policlinico San Martino, Genoa, Italy.
Marco Di Duca: UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Genoa, Italia, Italy.
Variants in the ACTG2 gene, encoding a protein crucial for correct enteric muscle contraction, have been found in patients affected with chronic intestinal pseudo-obstruction, either congenital or late-onset visceral myopathy, and megacystis-microcolon-intestinal hypoperistalsis syndrome. Here we report about ten pediatric and one adult patients, from nine families, carrying ACTG2 variants: four show novel still unpublished missense variants, including one that is apparently transmitted according to a recessive mode of inheritance. Four of the remaining five probands carry variants affecting arginine residues, that have already been associated with a severe phenotype. A de novo occurrence of the variants could be confirmed in six of these families. Since a genotype-phenotype correlation is affected by extrinsic factors, such as, diagnosis delay, quality of clinical management, and intra-familial variability, we have undertaken 3D molecular modeling to get further insights into the effects of the variants here described. The present findings and further ACTG2 testing of patients presenting with intestinal pseudo-obstruction, will improve our understanding of visceral myopathies, including implications in the prognosis and genetic counseling of this set of severe disorders.
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