Olfactory Malformations in Mendelian Disorders of the Epigenetic Machinery

Sebastiano Aleo; Claudia Cinnante; Sabrina Avignone; Elisabetta Prada; Giulietta Scuvera; Paola Francesca Ajmone; Angelo Selicorni; Maria Antonella Costantino; Fabio Triulzi; Paola Marchisio; Cristina Gervasini; Donatella Milani

doi:10.3389/fcell.2020.00710

Olfactory Malformations in Mendelian Disorders of the Epigenetic Machinery

Front Cell Dev Biol. 2020 Aug 4:8:710. doi: 10.3389/fcell.2020.00710. eCollection 2020.

Affiliations

¹ Pediatric Highly Intensive Care Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
² Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuroradiology Unit, Università degli Studi di Milano, Milan, Italy.
³ Child and Adolescent Neuropsychiatric Service (UONPIA), Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
⁴ Unit of Pediatric, Presidio S. Fermo, ASST Lariana, Como, Italy.
⁵ Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy.
⁶ Division of Medical Genetics, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.

Abstract

Usually overlooked by physicians, olfactory abnormalities are not uncommon. Olfactory malformations have recently been reported in an emerging group of genetic disorders called Mendelian Disorders of the Epigenetic Machinery (MDEM). This study aims to determine the prevalence of olfactory malformations in a heterogeneous group of subjects with MDEM. We reviewed the clinical data of 35 patients, 20 females and 15 males, with a mean age of 9.52 years (SD 4.99). All patients had a MDEM and an already available high-resolution brain MRI scan. Two experienced neuroradiologists reviewed the MR images, noting abnormalities and classifying olfactory malformations. Main findings included Corpus Callosum, Cerebellar vermis, and olfactory defects. The latter were found in 11/35 cases (31.4%), of which 7/11 had Rubinstein-Taybi syndrome (RSTS), 2/11 had CHARGE syndrome, 1/11 had Kleefstra syndrome (KLFS), and 1/11 had Weaver syndrome (WVS). The irregularities mainly concerned the olfactory bulbs and were bilateral in 9/11 patients. With over 30% of our sample having an olfactory malformation, this study reveals a possible new diagnostic marker for MDEM and links the epigenetic machinery to the development of the olfactory bulbs.

Keywords: epigenetics; mendelian disorders of the epigenetic machinery; nervous system diseases/genetics; neuroimaging; olfactory bulb; rare diseases.