Case Report
A Rare Case of Severe Congenital RYR1-Associated Myopathy
Nicola Laforgia ,
1
Manuela Capozza,
1
Lucrezia De Cosmo,
1
Antonio Di Mauro ,
1
Maria Elisabetta Baldassarre,
1
Francesca Mercadante,
2
Anna Laura Torella,
3
Vincenzo Nigro,
3
and Nicoletta Resta
2
1
Neonatology and Neonatal Intensive Care Unit, Department of Biomedical Science and Human Oncology,
“Aldo Moro” University of Bari, Policlinico Hospital, Piazza Giulio Cesare n. 11, 70124 Bari, Italy
2
Medical Genetics Unit, Department of Biomedical Sciences and Human Oncology, “Aldo Moro” University of Bari,
Policlinico Hospital, Piazza Giulio Cesare n. 11, 70124 Bari, Italy
3
Medical Genetics Laboratory, Department of Precision Medicine, “L.Vanvitelli” University of Campania,
Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
Correspondence should be addressed to Nicola Laforgia; nicola.laforgia@uniba.it
Received 12 February 2018; Revised 28 June 2018; Accepted 19 July 2018; Published 1 August 2018
Academic Editor: Balraj Mittal
Copyright © 2018 Nicola Laforgia et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Congenital myopathies are a group of rare inherited diseases, defined by hypotonia and muscle weakness. We report clinical and
genetic characteristics of a male preterm newborn, whose phenotype was characterized by severe hypotonia and hyporeactivity,
serious respiratory distress syndrome that required mechanical ventilation, clubfoot, and other dysmorphic features. e diagnostic
procedure was completed with the complete exome sequencing of the proband and of his parents and his sister, which showed new
mutations in the ryanodine receptor gene (RYR1), which maps to chromosome 19q13.2 and encodes the skeletal muscle isoform
of a calcium-release channel in the sarcoplasmic reticulum (RyR1). is report confirms that early diagnosis and accurate study of
genomic disorders are very important, enabling proper genetic counselling of the reproductive risk, as well as disease prognosis
and patient management.
1. Introduction
Congenital myopathies are a group of rare inherited diseases,
defined by hypotonia and muscle weakness, that usually
present at birth or early childhood, in association with
characteristic morphological defects. ey are caused by
genetic mutations of the structural proteins of skeletal muscle
and present variable inheritance: dominant, recessive, or X-
linked [1, 2].
Mutations in a single gene may be associated with
different clinical and histological findings, and the same
clinical or histological conditions may be due to mutations
in different genes [3]. Phenotypic findings include severe
neonatal-onset, mild forms with nonprogressive weakness,
and muscle hypotonia with later onset.
e old classification of congenital myopathies was
mainly based on histological features observed in the muscle
biopsy [1, 3]: myopathies with “rods” (nemaline myopathies),
myopathies with centralized nuclei (myotubular and cen-
tronuclear myopathies), myopathies with fiber type dispro-
portion, and myopathies with “cores” (oval areas in the
muscle cells) [4, 5]. e last ones are the most common forms
of congenital myopathies, in particular the “central core”
myopathy (CCD). e most known CCD is the autosomal
dominant inherited form caused by mutations localized in
three hot spots in the ryanodine receptor 1 gene (RYR1), asso-
ciated with malignant hyperthermia susceptibility (MHS)
and clinically characterized by minor hypotonia and nonpro-
gressive weakness. Recessive mutations are located through-
out the entire RYR1 gene and characterized by a more severe
and progressive clinical presentation with neonatal-onset and
significant generalized muscle weakness [6–8]
.
Commoner myopathy disorders presenting in fetal or
neonatal period are shown in Table 1.
Hindawi
Case Reports in Genetics
Volume 2018, Article ID 6184185, 7 pages
https://doi.org/10.1155/2018/6184185