Open AccessTrappc9 deficiency causes parent-of-origin dependent microcephaly and obesity
Author(s) -
Zhengzheng S. Liang,
Irène Cimino,
Binnaz Yalcin,
Narayanan Raghupathy,
Valerie E. Vancollie,
Ximena Ibarra-Soria,
Helen V. Firth,
Debra Rimmington,
I. Sadaf Farooqi,
Christopher J. Lelliott,
Steven C. Munger,
Stephen O’Rahilly,
Anne C. FergusonSmith,
Anthony P. Coll,
Darren W. Logan
Publication year - 2020
Publication title -
plos genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.587
H-Index - 233
eISSN - 1553-7404
pISSN - 1553-7390
DOI - 10.1371/journal.pgen.1008916
Subject(s) - biology , allele , microcephaly , genomic imprinting , genetics , imprinting (psychology) , phenotype , mutant , null allele , mutation , gene , gene expression , dna methylation
Some imprinted genes exhibit parental origin specific expression bias rather than being transcribed exclusively from one copy. The physiological relevance of this remains poorly understood. In an analysis of brain-specific allele-biased expression, we identified that Trappc9 , a cellular trafficking factor, was expressed predominantly (~70%) from the maternally inherited allele. Loss-of-function mutations in human TRAPPC9 cause a rare neurodevelopmental syndrome characterized by microcephaly and obesity. By studying Trappc9 null mice we discovered that homozygous mutant mice showed a reduction in brain size, exploratory activity and social memory, as well as a marked increase in body weight. A role for Trappc9 in energy balance was further supported by increased ad libitum food intake in a child with TRAPPC9 deficiency. Strikingly, heterozygous mice lacking the maternal allele (70% reduced expression) had pathology similar to homozygous mutants, whereas mice lacking the paternal allele (30% reduction) were phenotypically normal. Taken together, we conclude that Trappc9 deficient mice recapitulate key pathological features of TRAPPC9 mutations in humans and identify a role for Trappc9 and its imprinting in controlling brain development and metabolism.