ESPE Yearbook of Paediatric Endocrinology

Cell 187(16), 4176-4192 (2024). https://doi.org/10.1016/j.cell.2024.06.001. https://pubmed.ncbi.nlm.nih.gov/38959890/

Brief Summary: This translational study identified microdeletions on chromosome Xq23 disrupting the brain-expressed transient receptor potential channel 5 (TRPC5) in two unrelated boys with intense food-seeking behaviour, obesity, autism, anxiety, and maladaptive behaviour. These changes were shared with their mothers, who had obesity, anxiety, and postpartum depression. Analysis of exome data from the Genetics of Obesity Study cohort (n=984) uncovered seven rare coding TRPC5 variants in people with severe childhood-onset obesity, while data from the UK Biobank (~450,000) identified 369 variants in the general population linked to higher BMI. Generation of a knock-in mouse model with a human loss-of-function TRPC5 mutation revealed that TRPC5 regulates obesity, hyperphagia, maladaptive behaviour, and postpartum depression via hypothalamic proopiomelanocortin (POMC) and oxytocin (OXT) neurons.

Growing evidence suggests that innate or instinctive human behaviours fundamental for survival, such as food seeking, maternal care, self-preservation and socialization are genetically encoded by specific hypothalamic nuclei, though the exact mechanisms remain unclear [1,2]. This study identified microdeletions and rare variants in TRPC5 in humans as potential cause for monogenic obesity and identified the first susceptibility loci for postpartum depression and impaired maternal care [3]. The observed phenotypic effects were found to be regulated by TRPC5 via POMC and OXT neurons, providing new mechanistic insights into the regulation of obesity and postpartum depression. However, the study lacks detailed clinical characterization of affected individuals and their families to establish penetrance and mode of inheritance. While obesity and hyperphagia in TRPC5 carriers may be treated with the MC4R agonist, setmelanotide, future research is needed to investigate wether OXT receptor agonists/analogs may restore TRPC5 expression in OXT neurons, offering potential treatment for postpartum depression.

Taken together, these findings strongly support including TRPC5 in diagnostic gene panels for severe childhood-onset obesity, autism, and postpartum depression, as treatment options may be available in the future.

References: 1. de Araujo Salgado I, Li C, Burnett CJ, Rodriguez Gonzalez S, Becker JJ, Horvath A, Earnest T, Kravitz AV, Krashes MJ. Toggling between food-seeking and self-preservation behaviors via hypothalamic response networks. Neuron. 2023 Sep 20;111(18):2899-2917.e6. PMID: 37442130.2. Saper CB, Lowell BB. The hypothalamus. Curr Biol. 2014 Dec 1;24(23):R1111-6. PMID: 25465326.3. Guintivano J, Byrne EM, Kiewa J, et al. Meta-Analyses of Genome-Wide Association Studies for Postpartum Depression. Am J Psychiatry. 2023 Dec 1;180(12):884-895. doi: 10.1176/appi.ajp.20230053. Erratum in: Am J Psychiatry. 2023 Dec 1;180(12):894. doi: 10.1176/appi.ajp.20230053correction.