TY - JOUR A2 - Ban, Yoshiyuki AU - Li, Dong AU - Bhoj, Elizabeth AU - McCormick, Elizabeth AU - Wang, Fengxiang AU - Snyder, James AU - Wang, Tiancheng AU - Zhao, Yan AU - Kim, Cecilia AU - Chiavacci, Rosetta AU - Tian, Lifeng AU - Falk, Marni J. AU - Hakonarson, Hakon PY - 2016 DA - 2016/03/16 TI - Early Infantile Epileptic Encephalopathy in an STXBP1 Patient with Lactic Acidemia and Normal Mitochondrial Respiratory Chain Function SP - 4140780 VL - 2016 AB - A wide range of clinical findings have been associated with mutations in Syntaxin Binding Protein 1 (STXBP1), including multiple forms of epilepsy, nonsyndromic intellectual disability, and movement disorders. STXBP1 mutations have recently been associated with mitochondrial pathology, although it remains unclear if this phenotype is a part of the core feature for this gene disorder. We report a 7-year-old boy who presented for diagnostic evaluation of intractable epilepsy, episodic ataxia, resting tremor, and speech regression following a period of apparently normal early development. Mild lactic acidemia was detected on one occasion at the time of an intercurrent illness. Due to the concern for mitochondrial disease, ophthalmologic evaluation was performed that revealed bilateral midperiphery pigmentary mottling. Optical coherence tomography (OCT) testing demonstrated a bilaterally thickened ganglion cell layer in the perifovea. Skeletal muscle biopsy analysis showed no mitochondrial abnormalities or respiratory chain dysfunction. Exome sequencing identified a de novo c.1651C>T (p.R551C) mutation in STXBP1. Although mitochondrial dysfunction has been reported in some individuals, our proband had only mild lactic acidemia and no skeletal muscle tissue evidence of mitochondrial disease pathology. Thus, mitochondrial dysfunction is not an obligate feature of STXBP1 disease. SN - 2090-6544 UR - https://doi.org/10.1155/2016/4140780 DO - 10.1155/2016/4140780 JF - Case Reports in Genetics PB - Hindawi Publishing Corporation KW - ER -