Heart failure in a young patient with nonobstructive hypertrophic cardiomyopathy leads to a genetic neuromuscular disease diagnosis

Introduction: This case presents the diagnostic process of a nonobstructive hypertrophic cardiomyopathy as linked to neuromuscular disease, explained by a mutation in FHL1 gene, which is usually associated with X-linked Emery Dreifuss muscular dystrophy (EDMD). The aim of this presentation is to highlight the fact that, besides the common sarcomeric gene mutations causing HCM, the diagnostic workup should take into consideration other redflags (as in this case increased muscular enzymes and muscular symptoms evoked by anamnesis).

Case presentation: We present the case of a 40 year old male patient diagnosed with HCM, referred for evaluation in the setting of NYHA class II heart fai-lure symptoms. Clinical examination shows irregular heart rate, mild apical systolic heart murmur, symme-trical loss of muscular force especially at upper limb level, and laboratory tests identify chronically elevated enzymes of muscular cytolysis. ECG shows AF episodes. Transthoracic echocardiography reveals moderate biventricular thickening of the myocardium (maximal LV wall thickness 15 mm, RV free wall thickness of 9 mm), important longitudinal dysfunction with apical sparring and severe impairment of the diastolic function (restrictive physiology). CMR found late gadoli-nium enhancement (LGE) with non-specific disposi-tion. Taking into consideration the echocardiographic aspect, alongside neuromuscular symptoms, systemic amyloidosis was excluded by negative whole-body 99Tc-HMDP scintigraphy and multiple tissue biopsies. Electromyography showed a chronic myopatic tracing. Muscular biopsy confirmed the existence of a core-multiminicore myopathy. The multimodality diagnosis approach in a patient with heart failure confirms the existence of a muscular dystrophy with related cardiac impairment. The process of fully evaluating the pati-ent was completed by genetic testing, which found a likely pathogenic mutation in FHL1 gene, involved in the type 6 X-linked EDMD. As only a few families were reported with this association yet, some with an aggressive course, risk stratification of this patient remains a clinical challenge.

Conclusions: Since the patient is suffering from a severe cause of heart failure, he is scheduled for periodic full evaluation. Prognostic data for this gene mutation is scarce, and it is not known if common HCM risk calculators are applicable. Given the fact that he is found positive at genetic testing, first-degree relatives are expected to come in soon for genome analysis. The association between EDMD and HCM is not common. An attentive red-flag guided diagnostic approach of cardi-omyopathies allows a correct final classification of the disease, as genotype-phenotype correlations can vary.

ISSN – online: 2734 – 6382
ISSN-L 1220-658X
ISSN – print: 1220-658X
The Romanian Journal of Cardiology is indexed by:
ESC search engine
CODE: 379
CME Credits: 10 (Romanian College of Physicians)
This work is licensed under a Creative Commons Attribution 4.0 International License.