La distrofia miotónica es una entidad infrecuente, raramente asociada a la gestación debido a que las personas afectadas suelen presentar atrofia genital con. – MYOTONIC DYSTROPHY 1; DM1 – DYSTROPHIA MYOTONICA 1;; DYSTROPHIA MYOTONICA; DM;; STEINERT DISEASE. Transcript of DISTROFIA MIOTONICA DE STEINERT. ¿QUE ES? Enfermedad hereditaria autosomica dominante. Es la más frecuente en.

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CC HPO: A repeat length exceeding 50 CTG repeats is pathogenic Musova et al. Myotonic dystrophy is an autosomal dominant disorder characterized mainly by myotonia, muscular dystrophy, cataracts, hypogonadism, frontal balding, and ECG changes.

The genetic defect in DM1 results from an amplified trinucleotide repeat in the 3-prime untranslated region of a protein kinase gene. Disease severity varies with the number of repeats: The disorder shows genetic anticipation, with expansion of the repeat number dependent on the sex of the transmitting parent. Alleles of 40 to 80 repeats are usually expanded when transmitted by males, whereas only alleles longer than 80 repeats tend to expand in maternal transmissions.

Repeat contraction events occur 4. See also myotonic dystrophy-2 DM2;which is caused by mutation in the ZNF9 gene on chromosome 3q In adult-onset DM1, symptoms typically become evident in middle life, but signs can be detectable in the second decade. Harper provided a monograph on myotonic dystrophy that has been updated regularly.

Unlike the other muscular dystrophies, DM initially involves the distal muscles of the extremities and only later affects the proximal musculature. In addition, there is early involvement of the muscles of the head and neck.

Involvement of the extraocular muscles produces ptosis, weakness of eyelid closure, and limitation of extraocular movements.

Atrophy of masseters, sternocleidomastoids, and the temporalis muscle produces a characteristic haggard appearance. Bosma and Brodie demonstrated both myotonia and weakness in patients with swallowing and speech disability. Myotonia, delayed muscular relaxation following contraction, is most frequently apparent in the tongue, forearm, and hand.

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Myotonia is rarely as severe as in myotonia congenita and tends to be less apparent as weakness steinerr. Many of the muscle biopsy changes are nonspecific. Most commonly there are central nuclei and ring fibers.

Necrosis, regeneration, and increase of collagen are never as severe as in Duchenne muscular dystrophy.

In many cases there are target fibers, suggesting neurogenic dysfunction, but intramuscular nerves appear histologically normal Drachman and Fambrough, Ultrastructural studies show dilatation of T tubules or sarcoplasmic reticulum, whose contents may be unusually dense Milhaud et al. In some cases the surface membrane may be irregular, with reduplication of basal lamina.

From a series of neurophysiologic investigations of 24 patients with myotonic diatrofia, Jamal et al. The authors stated that ‘the concept of myotonic dystrophy as a pure myopathy can no longer be sustained. Thirteen members of a large family presented with a hereditary motor and sensory neuropathy in a dominant pedigree pattern.

Eight of the 13 affected members also showed more or less prominent signs of myotonic dystrophy.

Distrofia Miotonica de Steiner

There was no case of myotonic dystrophy alone. The correlation appeared to be more linear with age of onset. Myotonic patients also showed significantly more cortical atrophy than did controls. However, there was no relationship between atrophy or white matter hyperintense lesions and age, disease duration, or neuropsychologic impairment.


MRI lesions were associated with impaired psychometric performance, but the MRI findings of subcortical white matter lesions correlated only very weakly with the molecular findings. Lesions were symmetric, occurred in the subcortical white matter, and showed a predilection for the temporal lobe. There was some evidence of cerebral atrophy in the patients overall but no difference in IQ between patients and controls.

There was no correlation between number of pathologic CTG repeats and white matter lesions, and there was no correlation between intellectual impairment and white matter lesions, except in 1 patient who had a difficult birth and temporal lobe epilepsy. Three patients had marked thickening of the skull, which was associated with ossification of the falx in 2. Brain MRI showed multiple discrete and confluent areas of abnormal signal intensity throughout the subcortical white matter with predominant involvement of the frontal and anterior temporal lobes.

There was also diffuse thickening of the skull with ossification of the falx. In a study of 21 patients with myotonic dystrophy, Akiguchi et al. Magnetic resonance spectroscopy demonstrated a significant reduction of the neuronal marker N-acetylaspartate, even in young patients in whom imaging studies were still equivocal.

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Delaporte found that 15 DM patients with no or minimal muscle weakness demonstrated a homogeneous personality profile characterized by steunert, obsessive-compulsive, passive-aggressive, and schizotypic traits. Fourteen healthy control individuals and 12 patients with a mild form of muscle disease did not show the same trait homogeneity. Delaporte concluded that the personality disorders were not attributable to the adjustment to a disabling condition, but rather were primary manifestations of the genetic mutation.

Patients with congenital onset CTG repeats greater than 1, obtained the lowest scores in verbal attainment, frontal and executive functions, and general intelligence, consistent with mental retardation.

Patients with 50 to repeats showed age-dependent impairment in memory, frontal lobe, and temporal lobe function. Patients with to 1, repeats showed defects only in frontal and executive tasks.

Although there was a correlation between number of repeats and degree of muscle involvement for all patients, there was not a significant correlation between number of repeats and cognitive impairment, except for the congenital group.

By neuropathologic examination, Sergeant et al. Three patients had clinical evidence of cognitive impairment or mental retardation. In some of the patients, zteinert brain regions also had NFTs. The implication was that there may be 2 forms of myotonic dystrophy. They studied 18 families and found heart block in 4. In a single large kindred, Tokgozoglu et al. Left ventricular ejection fractions and stroke volume were reduced compared with normals.

Using multivariate analysis, the number of CTG repeats range, 69 to ; normal, less than 38 was the strongest predictor of abnormalities in wall motion and EKG conduction. The authors also found that the relation of mitral valve steiert to the distorfia of the CTG repeat was of borderline significance. Cardiac involvement is well described in adults with distorfia dystrophy. All patients were in sinus rhythm with a normal P wave axis.

Three had first-degree heart block and 4 had a borderline P-R interval ms. Four others had more complex conduction abnormalities. Three patients had mitral valve prolapse. Eleven of the 12 patients had abnormalities of 1 or more parameter of left ventricular diastolic filling.

None of these patients were strinert. The authors commented that the prognostic implications of these findings were unclear; however, they concluded that echocardiographic assessment of left ventricular diastolic function may be a useful adjunct to electrocardiographic monitoring of patients with congenital myotonic dystrophy.


Nineteen patients developed major cardiac distroofia during the month disstrofia. Two patients died suddenly, 1 patient had cardiac arrest with successful resuscitation, and 1 asymptomatic year-old girl presented with recurrent presyncope.

Rhythm disturbances included atrial flutter in 4, ventricular tachycardia in 4, and atrial fibrillation in 1. Five patients had atrioventricular block necessitating pacemaker implantation.

Genetic analysis detected between and 1, CTG repeats in all patients. No cardiac involvement was detected before age 10 years.

After a mean follow-up period of 5.


There were 27 sudden deaths, 32 deaths from progressive neuromuscular respiratory failure, 5 nonsudden deaths from cardiac causes, and 17 deaths from other causes. The miottonica cause of death in the cohort was respiratory failure associated with progressive muscular weakness.

A severe ECG abnormality and a clinical diagnosis of atrial tachyarrhythmia conferred relative risks for sudden death of 3. Harper observed that in a small proportion of cases, myotonic dystrophy may be congenital with neonatal hypotonia, motor and mental retardation, and facial diplegia.

With rare exception, it is the mother who transmits the disease. Diagnosis can be difficult if the family history is not known because muscle wasting may not be apparent, and cataracts and clinical myotonia are absent, although the latter is sometimes detectable by electromyography.

Talipes at birth, together with hydramnios and reduced fetal movements during pregnancy, is frequent. Respiratory difficulties are frequent and are often fatal. By age 10 they develop myotonia and in adulthood develop the additional disrrofia described for the adult-onset disease. Three of the 18 had died, and 5 were lost to follow-up.

The remaining 10 had IQs of less than Universal findings were language delay, hypotonia, and delayed motor development. There was no difficulty with routine immunizations nor were there anesthetic complications observed in any of the 7 patients who underwent surgery. Obstetric problems were inversely correlated with age at onset of maternal DM, while no effect of age at delivery or birth order on gestational outcome was seen.

Stratton and Patterson established the molecular diagnosis of myotonic dystrophy in a steineert shown to have bilateral effusions and scalp and upper torso edema by ultrasound examination at 30 weeks’ gestation.

Polyhydramnios was also present. Thus, nonimmune hydrops fetalis is a manifestation of congenital myotonic dystrophy. The mother had previously unsuspected myotonic dystrophy, but she did show grasp myotonia. Her brother had a confirmed diagnosis. The DM gene showed marked expansion in her fetus. Stratton and Patterson found reports of 15 other cases of nonimmune hydrops fetalis associated with congenital myotonic dystrophy. The hydropic infant stopped moving 8 weeks before delivery and did not move postnatally.

Autopsy revealed extensive CNS destruction of unknown cause. There is impaired responsiveness to follicle stimulating hormone with hypogonadism Sagel et al.

Di Chiro and Caughey reviewed radiographic findings in the skull in 18 cases. In 17, ‘hyperostotic’ dlstrofia in the vault were found, the sex distribution being equal. In 8 cases with hypogonadism, the hyperostosis was most advanced.