+ MODEL Journal of the Formosan Medical Association (2016) xx, 1e2 Available online at www.sciencedirect.com ScienceDirect journal homepage: www.jfma-online.com CORRESPONDENCE RusselleSilver syndrome presenting with ambiguous genitalia I-Fan Chang, Yin-Hsiu Chien, Wen-Yu Tsai, Ni-Chung Lee* Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan Received June 2016; received in revised form November 2016; accepted 14 November 2016 RusselleSilver syndrome (RSS) is a clinically heterogeneous condition characterized by severe intrauterine and postnatal growth retardation, relative macrocephaly, a triangular face, and body asymmetry Its most common etiologies are hypomethylation of the 11p15 H19/IGF2imprinting control region and maternal uniparental disomy of chromosome 7, which account for up to 60% and 5e10% of cases, respectively.1,2 Patients with hypomethylation are more likely to exhibit the classical features of RSS, whereas patients with maternal uniparental disomy of chromosome usually have learning difficulties.3 Genital anomalies have been described in RSS, but these are not considered to be symptoms of the disease A 17-month-old boy was born to a gravida 2, para mother at 37 weeks of gestation Neither parent had a family history of birth defects or genetic disorders Oligohydramnios was noted prenatally, and an amniocentesis revealed a normal (46,XY) male karyotype and normal array comparative genomic hybridization analysis At birth, the patient was extremely small for his gestational age, with a birth weight of 1440 g (below the 3rd percentile), but his head circumference was normal (33 cm; 10e25th percentile) He was noted to have ambiguous genitalia with a small phallus (2.5 cm in length) His gonads were palpable in the inguinal area (Figure 1A) His basal follicle-stimulating hormone, luteinizing hormone, testosterone, and E2 levels were 4.5 mIU/ mL, 4.98 mIU/mL, 1.29 ng/mL, and