A Patient with Kabuki (Niikawa-Kuroki) Syndrome, Common Variable Immunodeficiency and Immune-Mediated Neutropenia Found to Have a Novel Mutation in the KTM2D Gene.
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Neha Dunn, M.D., Rohit Katial, MD FAAAAI, Jenny Stitt, M.D.
Rationale: Kabuki syndrome (KS) is a rare, congenital, multiple anomaly syndrome characterized by distinctive facial features, global developmental delay, cardiovascular and musculoskeletal abnormalities.  Patients often have recurrent infections, specifically otitis media, and impaired immune function with antibody abnormalities consistent with common variable immunodeficiency (CVID) and lymphopenia. KS is frequently, but not always, caused by mutations in genes encoding histone-modifying proteins, specifically KMT2D and KDM6A. We describe a case of Kabuki syndrome with a novel mutation in the KMT2D gene.  

Methods: Serologic immune evaluation with bidirectional sequencing of the entire KMT2D coding region and intron-exon boundaries was performed. 

Results: Our patient is a 25 year old male with a previous clinical diagnosis of KS with characteristic facial features, type 1 diabetes mellitus and a history of coarctation of the aorta status post subclavian flap repair. He had recurrent infections with otitis media, sinusitis and two lifetime pneumonias. He was found to have hypogammaglobulinemia (IgG 147, IgA 13 and IgM of 42) and was started on IVIG replacement. He had refractory neutropenia treated with G-CSF, prednisone and eventually methotrexate. Upon genetic testing, he was found to have a novel mutation in the c.510+2T>C region of the KMT2D gene. Previous studies have identified mutations in KMT2D in 34-76% of patients with KS. While de novo mutations are common, the particular mutation in our patient has not been previously reported. 

Conclusions: This case describes a patient with KS, CVID and immune-mediated neutropenia with a mutation in the KMT2D gene, which has not previously been reported.