en Genetics & Disease Genetics & Disease Original Article Original Article <div style="text-align: justify;">Waardenburg syndrome (WS) is a neurocristopathy with an autosomal dominant mode of inheritance, and considerable clinical and genetic heterogeneity. WS type II is the most common type of WS in many populations presenting with sensorineural hearing impairment, heterochromia iridis, hypoplastic blue eye, and pigmentary abnormalities of the hair and skin. To date, mutations of <em>MITF</em>, <em>SOX10</em>, and <em>SNAI2</em> have been implicated in the pathogenesis of WS2. Although different pathogenic mutations have been reported in many ethnic groups, the data on Iranian WS2 patients is insufficient. 31 WS2 patients, including 22 men and 9 women from 14 families were included. Waardenburg consortium guidelines were employed for WS2 diagnosis. WS2 patients underwent screening for <em>MITF</em>, <em>SOX10</em>, and <em>SNAI2</em> mutations using direct sequencing and MLPA analysis. Clinical evaluation revealed prominent phenotypic variability in Iranian WS2 patients. Sensorineural hearing impairment and heterochromia iridis were the most common features (67% and 45%, respectively), whereas anosmia was the least frequent phenotype. Molecular analysis revealed a <em>de novo</em> heterozygous c.640C>T (p.R214X) in <em>MITF</em> and a <em>de novo</em> heterozygous <em>SOX10</em> gross deletion in the study population. Our data help illuminate the phenotypic and genotypic spectrum of WS2 in an Iranian series of patients, and could have implications for the genetic counseling of WS in Iran.</div> Waardenburg syndrome type 2, Iran, MLPA, gene deletion, mutation 17 23 http://ijmcmed.org/browse.php?a_code=A-10-1356-1&slc_lang=en&sid=1 Nazanin Jalilian n.jalilian@kums.ac.ir 100319475328460011381 100319475328460011381 No Department of Clinical biochemistry, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. Mohammad Amin Tabatabaiefar mamintab@yahoo.co.uk 100319475328460011382 100319475328460011382 No Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Mahboubeh Yazdanpanah yazdanpanah_iryas@yahoo.com 100319475328460011383 100319475328460011383 No Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Elham Darabi eli.darly@gmail.com 100319475328460011384 100319475328460011384 No Department of Medical Genetics, School of Medicine, International Campus, Tehran University of Medical Sciences, Tehran, Iran. Tayyeb Bahrami tayyeb_bahrami@yahoo.com 100319475328460011385 100319475328460011385 No Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Ali Zekri azekri87@gmail.com 100319475328460011386 100319475328460011386 No Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran. Mohammad Reza Noori-Daloii nooridaloii@tums.ac.ir 100319475328460011387 100319475328460011387 Yes Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.