Distrofia miotónica congénita. Hallazgos clínicos, electrofisiológicos y genéticos de nuestra casuística / Congenital myotonic dystrophy. Clinical, electrophysiological and genetic findings of our casuistry

Introducción. La distrofia miotónica congénita es una enfermedad multisistémica de herencia autosómica dominante, heredada generalmente a través de la madre, y que se caracteriza porque al nacimiento, el recién nacido presenta hipotonía, problemas respiratorios y alimenticios, debilidad facial y general. Objetivos. Estudio descriptivo de nuestra experiencia en la distrofia miotónica congénita. Pacientes y métodos. Se estudiaron 12 pacientes con distrofiamiotónica congénita, pertenecientes a 9 familias donde las madres eran portadoras de la enfermedad, y se analizaron las características clínicas, electromiográficas y genéticas. Resultados. El retraso motor era manifiesto en todos los pacientes, así como el retraso intelectual, la disartria y la voz nasal. Los niños afectados presentaban más de 1.500 repeticiones del trinucleótido citosina-timina-guanina del cromosoma 19 determinadas por la técnica de Southern Blot. Las alteraciones electromiográficas de tipo miopático estaban presentes en todos ellos. La biopsia muscular realizada a 8 pacientes mostraba atrofia y predominio de fibras tipo 1 con núcleos centrales e hipertrofia de fibras tipo 2. Conclusión. Es necesario sospechar la distrofia miotónicaante casos de recién nacidos con hipotonía, en madres conhistoria de abortos o recién nacidos muertos. Una vez superados los primeros años de vida, su desarrollo es similar al dela distrofia miotónica del adulto. Es fundamental realizar el estudio genético a los afectados y portadores de esta enfermedad (AU)

Introduction. Congenital myotonic dystrophyis an autosomal dominant inherited generally transmitted multisystemic disease that is generally inherited through themother. It is characterized by the birth the newborn baby with hypotonia, respiratory and nutritional problems, and facial and general weakness. Objective. Descriptive study of our experience in congenital myotonic dystrophy. Patients and methods. Twelve patients with congenital myotonicdy strophy, belonging to 9 families in which the mother was a carrier of the disease have been studied. The clinical, electromyographic and genetic characteristics of their familieswere analyzed. Results. Motor retardation as well as the intellectual retardation,dysarthria and nasal voice was clear in all the patients.The affected children had more than 1,500 repetitions of the cytosine-thymine-guanine (CTG) trinucleotide on chromosome 19 determined by the Southern Blot technique. Myopathictype alterations were found in the electromyographsof all of the subjects. The muscular biopsy done in 8 patients showed atrophy and predominance of type 1 fibers with centralnuclei and type 2 fiber hypertrophy. Conclusion. Myotonic dystrophy should be suspected incases of newborn babies with hypotonia, in mothers with a back ground of abortions or stillborn babies. After surviving the first years of life, their development is similar to the myotonicdy strophy of the adult. It is fundamental to perform agenetic study in those who are affected by or carriers of the disease (AU)

Does proximal myotonic myopathy show anticipation?

Proximal myotonic myopathy (DM2, PROMM) has not been reported in patients younger than 18 years, and apparent lack of congenital and childhood forms is thought to be one of the distinctive clinical characteristics of this trait. We now describe a 2-year-old boy, the youngest member of a family with a history for myotonia in 2 generations. The patient's 35-year-old mother was diagnosed with DM2 of late juvenile onset. She developed aggravating myotonic symptoms during pregnancy. Remarkably few intrauterine child movements were noticed. After birth the child showed general muscular hypotonia with delayed statomotoric development (sitting and crawling at 13 months, first lifting into standing position at 18 months). Muscle reflexes were normal. In the CL3N58 region of ZNF9, DM2-typical unstable expanded CCTG arrays of about 14.5 kb (about 2,500 repeats) were detected both in the mother and the patient by Southern blotting. Expansion of the DM1-specific DMPK CTG repeat was excluded.

Autism spectrum conditions in myotonic dystrophy type 1: a study on 57 individuals with congenital and childhood forms.

Myotonic dystrophy type 1 (DM1) is an autosomal dominant disorder, caused by an expansion of a CTG triplet repeat in the DMPK gene. The aims of the present study were to classify a cohort of children with DM1, to describe their neuropsychiatric problems and cognitive level, to estimate the size of the CTG expansion, and to correlate the molecular findings with the neuropsychiatric problems. Fifty-seven children and adolescents (26 females; 31 males) with DM1 (CTG repeats > 40) were included in the study. The following instruments were used: Autism Diagnostic Interview-Revised (ADI-R), 5-15, Griffiths Mental Development Scales, and the Wechsler Scales. Based on age at onset and presenting symptoms, the children were divided into four DM1 groups; severe congenital (n = 19), mild congenital (n = 18), childhood (n = 18), and classical DM1 (n = 2). Forty-nine percent had an autism spectrum disorder (ASD) and autistic disorder was the most common diagnosis present in 35% of the subjects. Eighty-six percent of the individuals with DM1 had mental retardation (MR), most of them moderate or severe MR. ASD was significantly correlated with the DM1 form; the more severe the form of DM1, the higher the frequency of ASD. The frequency of ASD increased with increasing CTG repeat expansions. ASD and/or other neuropsychiatric disorders such as attention deficit hyperactivity disorder, and Tourette's disorder were found in 54% of the total DM1 group. In conclusion, awareness of ASD comorbidity in DM1 is essential. Further studies are warranted to elucidate the molecular etiology causing neurodevelopmental symptoms such as ASD and MR in DM1.

Anesthetic management for subtotal gastrectomy in a patient with paramyotonia congenita.

We performed anesthesia for a subtotal gastrectomy in a 70-year-old female patient with paramyotonia congenita (PC). She had been diagnosed with PC at the age of 47 years by electromyogram analysis. Several points to consider have been revealed regarding the management of anesthesia in patients with PC. In this patient, anesthesia was safely maintained using sevoflurane and nitrous oxide together with concomitant epidural anesthesia using mepivacaine. Efforts should be made to prevent perioperative attacks of muscle weakness when planning anesthesia for patients with this kind of disorder. Specifically, refraining from the use of muscle relaxants, care with regard to the composition of infusion fluids during operations, and the maintenance of body temperature are required for anesthesia. In addition, postoperative pain management using a continuous epidural block proved to be a useful method.

Congenital myotonic myopathy in the miniature schnauzer: an autosomal recessive trait.

Myotonia is a clinical sign characterized by a delay in skeletal muscle relaxation following electrical or mechanical stimulation. A series of related miniature schnauzer dogs with congenital myotonic myopathy were studied. A composite pedigree of six affected litters and the results of a planned breeding between two affected animals are consistent with an autosomal recessive mode of inheritance.