Rubinstein-Taybi syndrome (RSTS) is a developmental disorder characterized by a wide spectrum of multiple congenital anomalies and cognitive impairment. RSTS is primarily due to mutations in CREBBP (approximately 55% of cases) or EP300 (approximately 8% of cases) genes. A 2 month-old boy had atypical facial findings such as low anterior hairline, triangular face, hirsutism on forehead, down-slanting palpebral fissures, beaked nose, broad nasal bridge, triangular mouth and pointed chin and skeletal finding including broad great thumbs and halluces, and accessory nipple. With this paper, we reported a novel frameshift mutation which is led to premature stop codon in CREBBP gene. As a result, c.2057dupC, reported in this paper enlarges the molecular spectrum of disease-causing CREBBP gene.