Coexistence of Kabuki Syndrome and Autoimmune Thyroiditis

Kabuki syndrome (KS) is a multiple congenital anomalies/intellectual disability syndrome characterized by developmental delay, specific facial features, skeletal and visceral abnormalities. This syndrome is caused by mutations in the MLL2 and KDM6A genes. The autoimmune abnormalities have been described in very rare patients with KS. Herein, we present a very rare condition, KS coexisting with autoimmune thyroiditis and vitiligo. A seven-year-seven-month-old girl presented with short stature. There was no consanguinity between her parents. She was born as a term neonate weighing 2100 gram as a twin baby with no perinatal complications. On physical examination, her typical facial features were large and low-set ears, broad and arched eyebrows, elongated palpebral fissures with eversion of the lateral third of the lower eyelid, high and narrow palate. Other phenotypic malformations were numerous vitiligo lesions of different size in the neck, brachydactyly, prominent fetal finger pads, and joint hyperlaxity. Her laboratory findings revealed autoimmune thyroiditis. Thyroid-stimulating hormone (TSH) was 242 mIU/L (reference range: 0.55-6.7) and free thyroxine (fT4) was 0.42 ng/dL (reference range: 0.91-1.92). Anti-microsomal antibody was 450.6 U/mL (reference range: 0-9) and anti-thyroglobulin antibody was 2766 U/mL (reference range: 0-4). Patient’s thyroid ultrasonography was consistent with thyroiditis with reduced parenchyma and rough pattern. Levothyroxine-replacement therapy (50 µg/day) induced euthyroid state (TSH: 3.65 mIU/L and fT4: 1.15 ng/dL). We detected a de novo heterozygous p.R2471* (c.7411C >T) mutation in the patient. No mutation was detected in the MLL2 gene in her parents and brother. To our knowledge, this mutation was not reported in KS patients to date.