We report a case of a 17-year-old Caucasian girl with syndromic features of clinically unrecognized Kabuki syndrome (KS), who developed systemic lupus erythematosus (SLE). Diagnosis of KS was established after whole exome sequencing (WES) and detection of de novo frameshift 1bp deletion in histone-lysine N-methyltransferase 2D gene (KMT2D). The pathogenic variant in exon 34 (c.8626delC: 55 reads C, 56 reads delC), has not been described previously and is predicted to truncate the protein (p.Gln2876Serfs*34) resulting in KMT2D loss of function. Notwithstanding that patients with KS have a substantial susceptibility to various autoimmune diseases, to the best of our knowledge this is the first report of an SLE and KS association. The exact relationship between the two conditions in our patient is difficult to determine with certainty, as a number of clinical features, including positive antiphospholipid antibodies, persistent hypogammaglobulinemia and the episode of convulsions may occur in both conditions, suggesting potential overlap of KS and SLE. The combination of a high susceptibility towards infections and an autoimmune disorder present a great challenge when trying to achieve the optimum therapy which will enable the patient to stay on the thin line of remission. This case report emphasizes the value of WES as a powerful tool for the diagnosis of rare disorders and/or unusual disease presentations of possible genetic cause.
Keywords: KMT2D; Kabuki syndrome; Systemic lupus erythematosus; Whole genome sequencing.
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