Homozygous Loss-of-Function Mutations in MNS1 Cause Laterality Defects and Likely Male Infertility

אסף תא-שמע ^1,2,13 Rim Hjeij ^3,13 Zeev Perles ¹ Gerard W. Dougherty ³ Ibrahim Abu Zahira ¹ Stef J.F. Letteboer ^4,5 Dinu Antony ^4,5,6 Alaa Darwish ¹ Dorus A. Mans ^4,5 Sabrina Spittler ³ Christine Edelbusch ³ Sandra Cindric ³ Tabea Nothe-Menchen ³ Heike Olbrich ³ Friederike Stuhlmann ³ Isabella Aprea ³ Petra Pennekamp ³ Niki T. Loges ³ Oded Breuer ⁷ Avraham Shaag ² Azaria JJT Rein ¹ Elif Yilmaz Gulec ⁸ Alper Gezdirici ⁸ Revital Abitbul ⁹ Nael Elias ¹⁰ Israel Amirav ^11,12 Miriam Schmidts ^4,5,6 Ronald Roepman ^4,5 Orly Elpeleg ² Heymut Omran ³

¹Pediatric Cardiology, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
²Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
³General Pediatrics, University Hospital Muenster, Muenster, Germany
⁴Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
⁵Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
⁶Pediatric Genetics Division, Faculty of Medicine, Freiburg University, Freiburg, Germany
⁷Pediatric Pulmonology, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
⁸Medical Genetics, University of Health Sciences, Istanbul, Turkey
⁹Pediatrics, Ziv Medical Center, Faculty of Medicine, Bar Ilan University, Safed, Israel
¹⁰Pediatrics, Saint Vincent Hospital, Faculty of Medicine, Bar Ilan University, Nazareth, Israel
¹¹Pediatrics, University of Alberta, Edmonton, Canada
¹²Pediatric Pulmonology, Tel Aviv Medical Center, Tel Aviv, Israel
¹³These authors, contributed equally to this work

The clinical spectrum of ciliopathies affecting motile cilia spans impaired mucociliary clearance in the respiratory system, laterality defects including heart malformations, infertility and hydrocephalus. Using linkage analysis and whole exome sequencing, we identified two recessive loss-of-function MNS1 mutations in four individuals from three consanguineous families. Three males from two families suffering from infertility, laterality defects and severe congenital heart defects shared a homozygous nonsense mutation, p.Arg242*, and one female had a homozygous nonsense mutation p.Gln203* in MNS1. Immunofluorescence analysis revealed that MNS1 is an axonemal protein of respiratory cilia as well as sperm flagella. Ultrastructural analyses confirmed a subtle outer dynein arm (ODA) defect in the axonemes of respiratory epithelial cells resembling findings reported in Mns1-deficient mice. Co-immunoprecipitation and yeast two hybrid analyses demonstrate that MNS1 dimerizes and also interacts with the ODA docking complex component CCDC114. Overall, we demonstrate that MNS1 deficiency in humans causes prominent laterality and male fertility defects resembling findings reported in Mns1-deficient mice.