Letter K

Abstract

Kabuki syndrome (Kabuki make-up syndrome, Niikawa-Kuroki Syndrome) is a rare multisystemic disorder characterized by a distinct face, postnatal growth deficiency, mild-to-moderate intellectual disability, skeletal and visceral malformations, and dermatoglyphic abnormalities. The disease is caused by mutations of 2 genes that function as epigenetic modulators: KMT2D (histone-lysine N-methyltransferase 2D) and KDM6A (lysine-specific demethylase 6A). Various human disorders have been linked to the mutations of genes involved in the epigenetic regulation—alterations of DNA and histone proteins that modulate gene expression in the absence of DNA mutations. These disorders share developmental faults, disrupted growth, multiple congenital organ defects, and hematological and immunological abnormalities. In fact, many patients with Kabuki syndrome experience low levels of serum immunoglobulin, increased susceptibility to infections, and a high risk of autoimmune diseases, including hemolytic anemia, idiopathic thrombocytopenic purpura, autoimmune thyroiditis, and vitiligo. Defects of B-cell terminal differentiation also have been described in patients with Kabuki syndrome.