Newborn screening for six lysosomal storage disorders in a cohort of Mexican patients: Three-year findings from a screening program in a closed Mexican health system Juana Inés Navarrete-Martínez a , Ana Elena Limón-Rojas b , Maria de Jesús Gaytán-García a , Jesús Reyna-Figueroa c , Guillermo Wakida-Kusunoki b , Ma. del Rocío Delgado-Calvillo d , Consuelo Cantú-Reyna e,f , Héctor Cruz-Camino e,g , David Eduardo Cervantes-Barragán a,h, ⁎ a Department of Genetics, Hospital Central Sur de Alta Especialidad, PEMEX, Mexico City, Mexico b General Dictatorate, Hospital Central Sur de Alta Especialidad, PEMEX, Mexico City, Mexico c Department of Medical Education and Research, Hospital Central Sur de Alta Especialidad, PEMEX, Mexico City, Mexico d Department of Pediatrics, Hospital Regional de Villahermosa, PEMEX, Villahermosa, Tabasco, Mexico e Genomi-k SAPI de CV. Monterrey, Nuevo León, Mexico f Escuela de Medicina Tecnológico de Monterrey, Monterrey, Nuevo León, Mexico g Escuela de Biotecnología y Ciencias de la Salud, Tecnológico de Monterrey, Monterrey, Nuevo León, Mexico h Facultad Mexicana de Medicina, Universidad La Salle, Mexico City, Mexico abstract article info Article history: Received 5 January 2017 Received in revised form 28 February 2017 Accepted 1 March 2017 Available online xxxx Objective: To evaluate the results of a lysosomal newborn screening (NBS) program in a cohort of 20,018 Mexican patients over the course of 3 years in a closed Mexican Health System (Petróleos Mexicanos [PEMEX] Health Ser- vices). Study design: Using dried blood spots (DBS), we performed a multiplex tandem mass spectrometry enzymatic assay for six lysosomal storage disorders (LSDs) including Pompe disease, Fabry disease, Gaucher disease, mucopolysaccharidosis type I (MPS-I), Niemann–Pick type A/B, and Krabbe disease. Screen-positive cases were confirmed using leukocyte enzymatic activity and DNA molecular analysis. Results: From July 2012 to April 2016, 20,018 patients were screened; 20 patients were confirmed to have an LSD phenotype (99.9 in 100,000 newborns). Final distributions include 11 Pompe disease, five Fabry disease, two MPS-I, and two Niemann–Pick type A/B patients. We did not find any Gaucher or Krabbe patients. A final frequen- cy of 1 in 1001 LSD newborn phenotypes was established. Discussion: NBS is a major public health achievement that has decreased the morbidity and mortality of inborn errors of metabolism. The introduction of NBS for LSD presents new challenges. This is the first multiplex Latin–American study of six LSDs detected through NBS. © 2017 Elsevier Inc. All rights reserved. Keywords: LSD Newborn screening Lysosomal storage disorder Fabry disease Pompe disease Gaucher disease Krabbe disease Mucopolysaccharidosis type I Niemann–Pick A/B 1. Introduction Lysosomal storage disorders (LSDs) constitute a diverse group of over 50 inherited metabolic disorders, with a collective incidence of 1 in 7000 to 9000 live births, due to a reduction or lack of lysosomal en- zymes, transport proteins, or impaired lysosomal enzyme biogenesis [1–3]. Progressive accumulation of metabolic precursors within the ly- sosomes result in cellular dysfunction and multiple organ damage [4, 5]. Recently, LSDs have been recognized as diseases that could greatly benefit from newborn screening (NBS). Currently, LSDs NBS programs have been developed for Pompe disease, Fabry disease, Gaucher disease, mucopolysaccharidosis type I (MPS-I), Niemann–Pick type A/B, and Krabbe disease (Table 1). Mexico's health system is fragmented into seven different health care providers that serve the population according to the employer's compulsory contributors and unemployed social security providers [6]. For instance, PEMEX (Petróleos Mexicanos Oil Company) Health Services covers oil company workers and their families, accounting for approximately 1%–1.5% of the entire Mexican population. PEMEX Health System's NBS program was established in 2005, and aims to de- tect inborn errors of metabolism (amino acid disorders, organic acidemias, etc.), monogenic disorders (inherited hemoglobin disorders, cystic fibrosis, congenital adrenal hyperplasia) [7], and NBS for hearing Molecular Genetics and Metabolism xxx (2017) xxx–xxx ⁎ Corresponding author at: Department of Genetics, Hospital Central Sur de Alta Especialidad, PEMEX, Periférico Sur 4091, Colonia Fuentes del Pedregal, Delegación Tlalpan 14140, Ciudad de México, Mexico. E-mail address: david.eduardo.cervantes@pemex.com (D.E. Cervantes-Barragán). YMGME-06158; No. of pages: 6; 4C: http://dx.doi.org/10.1016/j.ymgme.2017.03.001 1096-7192/© 2017 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Molecular Genetics and Metabolism journal homepage: www.elsevier.com/locate/ymgme Please cite this article as: J.I. Navarrete-Martínez, et al., Newborn screening for six lysosomal storage disorders in a cohort of Mexican patients: Three-year findings from a screening progra..., Mol. Genet. Metab. (2017), http://dx.doi.org/10.1016/j.ymgme.2017.03.001