ESPE Abstracts

1q21.1 recurrent microdeletion syndrome is a rare chromosomal disorder caused by a genetic abnormality of non-allelic homologous recombination in the sequence of flanking a copy number variation event during meiosis. The characteristic features of 1q21 microdeletion syndrome are dysmorphic facial appearances with microcephaly, and mild to moderate developmental delay of speech and motor, eye abnormality, short stature, skeletal malformation, and psychiatric and behavioral disorders. Only a few people have autism spectrum disorder or brain malformation. In this report, there is a 9-year-old female from non-consanguineous parents who came to the clinic because of short stature with breast budding. Complete growth hormone deficiency with elevated basal and stimulated LH was revealed by growth hormone and gonadotropin releasing hormone stimulation test. The girl also presented microcephaly with a dysmorphic facial appearance including frontal bossing, prominent nasal bridged with a bulbous tip, full cheek, and short neck. Short stature with brachydactyly of 4-5^th metacarpal hypoplasia and lumbar scoliosis was found by skeletal X-ray analysis. She had behavior problems derived by mood disorder and slightly low intelligence (Full scale intelligence quotation 80, Korean Wechsler Intelligence Scale of Children-IV). The brain abnormality was not found by brain magnetic resonance imaging. Based on these characteristics, microarray-based comparative genomic hybridization was conducted and revealed microdeletion at chromosome 1q21.1 and 1q21.1q21.2. Furthermore, chromosomal microarray analysis of both parents revealed that her mother has the same chromosomal defects on 1q21.1, even though she did not show characteristic phenotypic features except short stature. 1q21.1 recurrent microdeletion syndrome should be suspected in patients with developmental delay, mild to moderate intellectual disability, mild dysmorphic facial appearances and microcephaly. Since these genetic diseases have variable phenotypic expressivity, this case can help clinician to know how they assess a patient with mild dysmorphic facial features and intellectual disability at the scene of clinic and to apply appropriate diagnostic tools for genetic confirmation