16194 A GAPO syndrome case report: Identification of novel biallenic ANTXR1 variants cause GAPO syndrome

Abstract

GAPO syndrome (GS) is a very rare disorder characterized by growth retardation, pseudoanodontia, alopecia and optic atrophy. We report a 20-year-old boy, except optic atrophy combined with a new discovered mutation. The patient was noticed to have abnormal facial features at birth, but no one knew what was exactly abnormality. He was discovered getting this syndrome since 12-year-old. On examination, the patient had short feature, universal alopecia, redundant skin, cafe-au-lait macules on the scalp, osteomalacia, and pseudoanodontia. He also had a typical face for GS including high and bossing forehead, puffy eyelids, depressed nasal bridge, cranofacial dysmorphia, thick everted lower lip, low-set ears, premature aging appearance and prominent dilated scalp veins. Primary and permanent teeth were formed but fail to erupt. The development of his mental and motor functional activities was not discovered abnormalities on examination. Laboratory examination was normal. The histopathologic pattern of the scalp skin described the epidermis had an atrophic malpighian layer, the epidermal ridges did not descend in the dermis and there was a dense proliferation of connective tissue admixed with infiltration of a chronic inflammatory cell. New mutations were discovered including a novel biallenic variants of ANTXR1: c.T1149 A (protein Y383X) and c.1143_1145del (protein Y383del) located both in exon 15 by whole exome sequencing. These variants are inherited from paternal indicated the auto recessive mode of inheritance. To date, only 6 mutations in ANTXR1 have been reported in GS. This is a first case of GS due to a novel biallenic ANTXR1 variants.