*Correspondence: tainamaiacardoso@gmail.com.
Abstract
Case Presentation: A 15-year-old patient has been presenting progressive weakness for about six months.
He reports that he can no longer play football like he used to and that long walks
are increasingly difficult to tolerate. Creatine phosphokinase (CPK) dosage was requested,
which was 5200 U/L and phase deletion of exons three to 16 of the dystrophin gene.
The mother's CPK dosage was also requested, within the normal range. Past history
of Autistic Spectrum Disorder diagnosis at age five, without continuous medication
use.
Discussion: Becker Muscular Dystrophy (BMD) is a rare disorder determined by gene mutation at
locus 21 on the short arm of the X chromosome. It presents elevated CPK levels, in
addition to a myopathic pattern on electroneuromyography (rapidly recruited motor
unit potentials of short duration and low amplitude). The clinical presentation is
variable, with tiptoe walking or exercise-related cramps. Muscle weakness can lead
to functional difficulties, being proximally symmetrical with lower limbs more affected
than upper limbs. Joint contractures and dilated myocardiopathy may occur. BMD is
allelic to Duchenne Muscular Dystrophy (DMD) but has a milder phenotype and longer
survival. Autism Spectrum Disorder (ASD) is a disorder characterized by impaired language,
social interaction, repetitive behaviors and restricted interests. Although the occurrence
of ASD in patients with DMD is rare (3-5%), the risk is 2 to 3 times higher than in
the general population, probably due to mutations in the distal portion of the dystrophin
gene, after exon 45. Since the signs and symptoms of ASD appear earlier than those
of DMD, and one of the early symptoms is walking on tiptoe, it is not uncommon for
patients to have a delayed diagnosis of dystrophy. The diagnosis can be confirmed
from the genetic study of dystrophin or through immunohistochemical study of the protein
in muscle tissue. The treatment consists of corticotherapy, which promotes increased
walking time, associated with motor and respiratory physiotherapy. The preventive
use of non-invasive ventilatory support and the use of myocardial fibrosis remodeling
drugs have modified modified the survival of the disease.
Final Comments: The suspected causes of ASD are as diverse as the spectrum itself, and reflect the
intrauterine environment, the child's early life, and genetic inheritance. Identifying
early signs and symptoms and recognizing its correlation with muscular dystrophy is
essential for a better prognosis.
