Myotonic Dystrophy Type 1: Case Reports

Introduction: Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder with multisystem involvement: skeletal and smooth muscles, eye, heart, endocrine, and central nervous system (CNS). The etiology is genetic, and it is transmitted in an autosomal dominant manner. The genetic defect consists of a trinucleotide CTG repeat expansion in the 3′ untranslated region of the DMPK gene (on chromosome 19q13.3).

Objective: The objective of our report is to contribute to the epidemiological data of this disease and to inform pediatricians from multiple domains, as the disease requires a multidisciplinary approach.

Methods: We present two illustrative cases of pediatric patients (male, 17 years old, respectively female, 13 years old) diagnosed with DM1. The patients were questioned, clinically examined, multidisciplinary evaluated, and genetically tested in our clinic.

Results: The male patient presented with bilateral blepharoptosis, myopathic facies, and bilateral hand myotonia. He also had cardiac involvement and reduced minimal and maximal inspiratory pressure on spirometry. The female patient only presented bilateral hand myotonia without any other organ or system affected. The diagnosis was confirmed by genetic testing in both of them.

Conclusions: We highlight the involvement of multiple systems and organs in DM1 in order to raise awareness about the disease manifestations among pediatricians, pediatric neurologists, cardiologists, ophthalmologists, endocrinologists, and the importance of a multidisciplinary team comprising of the aforementioned specialties.