Myotonic dystrophy 2 manifesting with non-alcoholic and non-hepatitic liver cirrhosis

Gastrointestinal involvement in neuromuscular disorders

Although not often discussed, many of the neuromuscular disorders (NMDs) affect the gastrointestinal tract (GIT). Depending on the type of NMD, the prevalence of GIT involvement ranges from <5% (e.g. hereditary neuropathies, myofibrillar myopathies) to 100% (e.g. MNGIE, OPMD). Particularly in NMDs with multisystem affection, involvement of the GIT can dominate the clinical presentation or at least make up a significant part of the clinical picture. The most prominent representatives of NMDs with multisystem involvement are the mitochondrial disorders (MIDs) and the myotonic dystrophies. The best known syndromic MIDs with GIT involvement are MNGIE, MELAS, Leigh, and Pearson syndromes. Among neuropathies, GIT involvement is most commonly found in ALS and GBS. GIT involvement may also be a feature of myasthenia. The clinical manifestations of GIT involvement are diverse and can affect the entire GIT, from the teeth to the rectum, including the liver and pancreas. The most well-known clinical manifestations of GIT involvement are dysphagia, nausea, vomiting, reflux, hollow organ dysmotility, hepatopathy, diabetes, diarrhea, constipation, and fecal incontinence. Even if treatment can usually only be symptomatic, the therapeutic options are diverse, are often effective, and can significantly and beneficially influence the course of the underlying NMD.

Parent-of-Origin Effect on the Age at Symptom Onset in Myotonic Dystrophy Type 2

Background and Objectives

The existence of clinical anticipation, congenital form, and parent-of-origin effect in myotonic dystrophy type 2 (DM2) remains uncertain. Here, we aimed at investigating whether there is a parent-of-origin effect on the age at the first DM2-related clinical manifestation.

Methods

We identified patients with genetically confirmed DM2 with known parental inheritance from (1) the electronic medical records of our institutions and (2) a systematic review of the literature following the PRISMA 2020 guidelines and recorded their age at and type of first disease-related symptom. We also interrogated the Myotonic Dystrophy Foundation Family Registry (MDFFR) for patients with DM2 who completed a survey including questions about parental inheritance and age at the first medical problem which they related to their DM2 diagnosis.

Results

A total of 26 patients with DM2 from 18 families were identified at our institutions as having maternal (n = 14) or paternal (n = 12) inheritance of the disease, whereas our systematic review of the literature rendered a total of 61 patients with DM2 from 41 families reported by 24 eligible articles as having maternal (n = 40) or paternal (n = 21) inheritance of the disease. Both cohorts were combined for downstream analyses. Up to 61% and 58% of patients had muscle-related symptoms as the first disease manifestation in maternally and paternally inherited DM2 subgroups, respectively. Four patients developed hypotonia at birth and/or delayed motor milestones early in life, and 7 had nonmuscular presentations (2 had cardiac events within the second decade of life and 5 had cataracts), all of them with maternal inheritance. A maternal inheritance was associated with an earlier (within the first 3 decades of life) age at symptom onset relative to a paternal inheritance in this combined cohort, and this association was independent of the patient's sex (OR [95% CI] = 4.245 [1.429-13.820], p = 0.0117). However, this association was not observed in the MDFFR DM2 cohort (n = 127), possibly because age at onset was self-reported, and the information about the type of first symptom or medical problem that patients related to DM2 was lacking.

Discussion

A maternal inheritance may increase the risk of an early DM2 onset and of cataracts and cardiovascular events as first DM2 manifestations.

Non-alcoholic fatty liver disease later diagnosed as myotonic dystrophy

BACKGROUND

Myotonic dystrophy (MD) is sometimes accompanied by metabolic/endocrine disorders, including dyslipidemia, central obesity, and hypogonadism. Due to considerable individual differences in the severity and progression of myopathy, MD patients with minimal-to-mild muscle symptoms might be followed as having other diseases, such as non-alcoholic fatty liver disease (NAFLD).

CASE SUMMARY

A 40-year-old non-obese man without a history of regular ethanol consumption was referred to our hospital due to persistent liver dysfunction and hyperlipidemia. His body mass index was 23.4 kg/m². Liver histology demonstrated macrovesicular steatosis, ballooned hepatocytes with eosinophilic inclusion bodies, and perisinusoidal fibrosis, leading to the diagnosis of non-alcoholic steatohepatitis (NASH). Although he had no discernable muscle pain or weakness, persistently high serum creatine kinase (CK) and myoglobin levels as well as the presence of frontal baldness, a hatched face, history of cataract surgery, and grip myotonia indicated the possibility of MD. Southern blotting of the patient’s DNA revealed the presence of CTG repeats, confirming the diagnosis.

CONCLUSION

When gastroenterologists encounter NAFLD/NASH patients, serum CK should be verified. If hyperCKemia, frontal baldness, a hatched face, history of cataract surgery, and grip myotonia are noted, the possibility of MD may be considered.

Dystrophia myotonica type 1 presenting with dysarthria: A case report and literature review

Dystrophia myotonica (DM) type 1 is an autosomal dominant disorder, caused by a trinucleotide CTG repeat expansion in the 3′ untranslated region of the dystrophia myotonica protein kinase (DMPK) gene (chromosome 19q13.3). The disorder affects different organ systems, including the skeletal muscles, ocular lens, lungs, heart and gastrointestinal tract, as well as the endocrine and central nervous systems. The skeletal muscles are most frequently involved, whereby the disorder manifests as myotonia, muscle weakness and amyotrophy. However, DM type 1 presenting with dysarthria is rare. The current study presents a case of a 28-year-old male with DM type 1 presenting with dysarthria and associated multifocal hyperintense lesions in the white matter. Although electromyogram measurements identified myotonic discharges in all extremities, a muscle biopsy failed to detect the characteristic pathological features of DM type 1. A lack of a positive family history for DM type 1 also obscured diagnosis. However, genetic analysis detected a single allele in the P12 segment of the DMPK gene that included a CTG expansion of 13 repeats and a three-base gradient fragment in the P134 segment that included a CTG expansion of >600 repeats. According to the characteristics of dysarthria, multifocal hyperintense lesions in the white matter, electromyogram measurement results and genetic testing results, a diagnosis of DM type 1 was confirmed.