Jae Lee, professor Department of Biological Sciences Scientists have known for years that mutations in the MLL4 gene can cause Kabuki syndrome, a rare developmental disorder. But a study published on Jan. 11 in Nature Communications illuminates new details regarding how this occurs. The research suggests that MLL4 controls the production of neurons that secrete growth hormone-releasing hormone (GHRH) in a part of the brain called the hypothalamus. Mice without working copies of the MLL4 gene in this area had stunted growth and markedly fewer GHRH neurons. Mice with only one functioning copy of the gene had similar problems. These are important insights, as GHRH stimulates production of the growth hormone in the pituitary gland in both mice and people. While the effects of Kabuki syndrome vary, delayed growth and short stature are common among patients.