@article {1005, title = {Constrained chromatin accessibility in PU.1-mutated agammaglobulinemia patients.}, journal = {J Exp Med}, volume = {218}, year = {2021}, month = {2021 Jul 05}, abstract = {

The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro-B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro- to pre-B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1{\textquoteright}s critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.

}, issn = {1540-9538}, doi = {10.1084/jem.20201750}, author = {Le Coz, Carole and Nguyen, David N and Su, Chun and Nolan, Brian E and Albrecht, Amanda V and Xhani, Suela and Sun, Di and Demaree, Benjamin and Pillarisetti, Piyush and Khanna, Caroline and Wright, Francis and Chen, Peixin Amy and Yoon, Samuel and Stiegler, Amy L and Maurer, Kelly and Garifallou, James P and Rymaszewski, Amy and Kroft, Steven H and Olson, Timothy S and Seif, Alix E and Wertheim, Gerald and Grant, Struan F A and Vo, Linda T and Puck, Jennifer M and Sullivan, Kathleen E and Routes, John M and Zakharova, Viktoria and Shcherbina, Anna and Mukhina, Anna and Rudy, Natasha L and Hurst, Anna C E and Atkinson, T Prescott and Boggon, Titus J and Hakonarson, Hakon and Abate, Adam R and Hajjar, Joud and Nicholas, Sarah K and Lupski, James R and Verbsky, James and Chinn, Ivan K and Gonzalez, Michael V and Wells, Andrew D and Marson, Alex and Poon, Gregory M K and Romberg, Neil} } @article {681, title = {Characterization of Rare Variants in MC4R in African American and Latino Children With Severe Early-Onset Obesity.}, journal = {J Clin Endocrinol Metab}, volume = {104}, year = {2019}, month = {2019 Jul 01}, pages = {2961-2970}, abstract = {

CONTEXT: Mutations in melanocortin receptor (MC4R) are the most common cause of monogenic obesity in children of European ancestry, but little is known about their prevalence in children from the minority populations in the United States.

OBJECTIVE: This study aims to identify the prevalence of MC4R mutations in children with severe early-onset obesity of African American or Latino ancestry.

DESIGN AND SETTING: Participants were recruited from the weight management clinics at two hospitals and from the institutional biobank at a third hospital. Sequencing of the MC4R gene was performed by whole exome or Sanger sequencing. Functional testing was performed to establish the surface expression of the receptor and cAMP response to its cognate ligand α-melanocyte-stimulating hormone.

PARTICIPANTS: Three hundred twelve children (1 to 18 years old, 50\% girls) with body mass index (BMI) >120\% of 95th percentile of Centers for Disease Control and Prevention 2000 growth charts at an age <6 years, with no known pathological cause of obesity, were enrolled.

RESULTS: Eight rare MC4R mutations (2.6\%) were identified in this study [R7S, F202L (n = 2), M215I, G252D, V253I, I269N, and F284I], three of which were not previously reported (G252D, F284I, and R7S). The pathogenicity of selected variants was confirmed by prior literature reports or functional testing. There was no significant difference in the BMI or height trajectories of children with or without MC4R mutations in this cohort.

CONCLUSIONS: Although the prevalence of MC4R mutations in this cohort was similar to that reported for obese children of European ancestry, some of the variants were novel.

}, issn = {1945-7197}, doi = {10.1210/jc.2018-02657}, author = {De Rosa, Maria Caterina and Chesi, Alessandra and McCormack, Shana and Zhou, Justin and Weaver, Benjamin and McDonald, Molly and Christensen, Sinead and Liimatta, Kalle and Rosenbaum, Michael and Hakonarson, Hakon and Doege, Claudia A and Grant, Struan F A and Hirschhorn, Joel N and Thaker, Vidhu V} }