Received: 11 February 2020 Revised: 2 July 2020 Accepted: 2 July 2020 DOI: 10.1111/ahg.12401 ORIGINAL ARTICLE Clinical and exome sequencing findings in seven children with Bardet–Biedl syndrome from Turkey Evren Gumus 1, 2 Ebru Tuncez 3 Ozlem Oz 1 Merve Saka Guvenc 4 1 Department of Medical Genetics, Faculty of Medicine, University of Harran, Sanliurfa, Turkey 2 Department of Medical Genetics, Faculty of Medicine, University of Mugla Sitki Kocman, Mugla, Turkey 3 Clinic of Medical Genetics, Sanliurfa Training and Research Hospital, Sanliurfa, Turkey 4 Genetic Diagnosis Center, Tepecik Training and Research Hospital, University of Health Sciences, Izmir, Turkey Correspondence Evren Gumus, MD, Faculty of Medicine, Department of Medical Genetics, Univer- sity of Mugla Sitki Kocman, Mugla, Turkey. Email: evreng@ymail.com Abstract Background: Bardet–Biedl syndrome (BBS) is a very-rare autosomal recessive genetic disorder with severe multisystem manifestations. Genetic testing plays an important role in the early diagnosis of the disease. In this study, while trying to elucidate the genetic etiology of seven individuals with clinical BBS diagno- sis from six different families, we also aimed to examine the distribution of BBS variations in this region of Turkey. Methods and materials: Exome sequencing analysis is performed for clinically diagnosed patients with BBS in the present study followed by parental segrega- tion. The unreported and previously described clinical features are presented. Results: Homozygous variants, four of which are unreported, in BBS-related genes (BBS5 [c.682-2A > G], MKKS [c.775del], BBS7 [c.849+1G > T], BBS9 [c.965G > A], BBS10 [c.145C > T], LZTFL1[c.384G > A]) are detected for all the seven individuals included in the study. The most common clinical finding is polydactyly followed by renal anomalies. The clinical features not previously described are correlated to the unreported variant. Conclusions: In this study, exome sequencing findings are discussed and four previously unreported disease-associated variants are described including the fifth BBS-implicated LZTFL1 change and possible genotype–phenotype correla- tion is described. KEYWORDS Bardet–Biedl Syndrome, BBS, exome sequencing, LZTFL1, variant 1 INTRODUCTION Bardet–Biedl syndrome (BBS) is a very rare autosomal recessive genetic disorder with severe multisystem mani- festations. The syndrome is characterized primarily by rod- cone dystrophy, postaxial polydactyly, obesity, intellectual disability, hypogonadism/genital abnormalities and renal anomalies; and secondarily by speech disorder, develop- mental delay, behavioral abnormalities, eye anomalies, brachydactyly/syndactyly, ataxia, hypertonia, anosmia, oral and dental abnormalities, cardiac anomalies, hepatic involvement, dysmorphism, Hirschsprung disease, and diabetes mellitus. The presence of four primary findings or three primary findings and two secondary findings is diagnostic (Beales et al., 2001; Beales, Elcioglu, Woolf, Parker, & Flinter, 1999; Billingsley et al., 2010; Forsythe & Beales, 2013; Warburg & Riise, 2000). According to the diagnostic criteria, it is not always possible to diagnose this syndrome at an early age, the most important reason for this is that some findings such as obesity, rod-cone dys- trophy, anosmia, and behavioral abnormalities manifest as the age progresses. In this context, genetic tests play Ann Hum Genet. 2020;1–10. © 2020 John Wiley & Sons Ltd/University College London 1 wileyonlinelibrary.com/journal/ahg