Defining the CIAO1-related disease spectrum: clinical and molecular insights into a novel defect in cytoplasmic iron-sulfur cluster assembly


Topic:

Translational Research

Poster Number: 329 T

Author(s):

Rotem Or Bach, MD, National Institute of Neurological Disorders and Stroke (NINDS)/NIH, Reza Maroofian, PhD, University College London, Georg M. Stettner, MD, University Children's Hospital Zurich, Johanna Herwig, University Medical Center Hamburg-Eppendorf, Elena Pegoraro, PhD, University of Padova, Veronique Manel, University Hospitals of Lyon, Shams Ribault, University Hospitals of Lyon, Francoise Bouhour, MD, University Hospitals of Lyon, Ana Topf, PhD, John Walton Muscular Dystrophy Research Centre, Pinki Munot, MD, UCL Great Ormond Street Institute of Child Health, Khalid Hama Salih, Sulaimani University, Iraq, Nebal W. Saadi, University of Baghdad, Sumit Verma, MD, Emory University School of Medicine, Tracey Willis, MD, The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust, Oswestry, UK, Stojan Peric, MD, PhD, University Clinical Centre of Serbia, Deepa Krishnakumar, Cambridge University Hospitals NHS Foundation Trust, Judit Szamosújvári, Children's Hospital of Central Switzerland, Angela Petrosino, University of Padova, Luca Bello, MD, University of Padova, Theresia Herget, University Medical Center Hamburg-Eppendorf, Jessika Johannsen, University Medical Center Hamburg-Eppendorf, Juliane Mueller, UCL Great Ormond Street Institute of Child Health, Sniya Sudhakar, Great Ormond Street NHS Trust Hospital, A. Reghan Foley, MD, MD(Res), Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, National Institutes of Health, Svetlana Gorokhova, MD, PhD, NIH/NINDS/NNDCS, Caroline Sewry, UCL Great Ormond Street Institute of Child Health, Anna Sarkozy, MD, UCL Great Ormond Street Institute of Child Health, Tracey A. Rouault, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)/NIH, Henry Houlden, University College London, Carole Vuillerot, MD, Hôpital Mère Enfant, Nathalie Streichenberger, Université Claude Bernard Lyon, Sandra Donkervoort, MS, Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, National Institutes of Healt, Volker Straub, MD, PhD, John Walton Muscular Dystrophy Research Centre, Francesco Muntoni, MD, Dubowitz Neuromuscular Centre, UCL and Great Ormond Street Hospital Trust, London, UK, Nunziata Maio, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)/NIH, Carsten G. Bönnemann, MD, habil., Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, National Institutes of Health

Loss of function in CIAO1, a key component of the cytoplasmic iron-sulfur cluster assembly (CIA) complex, has recently been linked by our group and others to a novel neuromuscular disorder and a lethal neurodegenerative phenotype, with clinical severity reflecting the extent of functional disruption caused by the reported variants. In this study, we expand the clinical and biochemical understanding of CIAO1-related disease by analyzing a larger cohort of affected individuals (n=12) and characterizing reported and newly identified disease-causing variants (n=9). Our cohort consists of 5 males and 7 females from 10 families, median age of 16.5 years, (range: 4-60 years) and includes two patients with novel homozygous genotypes: c.817G>C, p.(Asp273His) presenting with childhood-onset limb-girdle muscular dystrophy (LGMD) without CNS or systemic involvement, and c.645C>A, p.(Asp215Glu) presenting at one year with global developmental delay and muscle weakness and death at age 4 years following a respiratory infection. Biallelic c.905A>C, p.(His302Pro) in trans with c.193C>T, p.(Arg65Trp) has now been identified in eight individuals as a recurrent genotype. It is associated with a phenotypic spectrum of muscle and neurobehavioral symptoms, with an age of onset ranging from birth to 15 years. Four of the eight patients show clinical features compatible with autism spectrum disorder, while the remaining four reported academic and/or cognitive difficulties. Notably, increased iron deposition in the brain deep nuclei has been observed in 5 patients.
Functional characterization of the variants revealed a strong correlation between the turnover rates of the mutated proteins and the severity of clinical features. Collectively, our study defines the clinical and biochemical landscape of the newly defined CIAO1-related disorder and advances our understanding of how CIA loss of function leads to multisystem manifestations, with predominant neuromuscular involvement.