Isolated left ventricular apical hypoplasia is a very rare anomaly with a broad range of clinical presentations. Mutation in the Lamin A/C gene has been regarded as a possible cause of this heart disease. The present study describes the case of an adolescent with isolated left ventricular apical hypoplasia and arthrogryposis without mutation in the Lamin A/C gene and conducts a review of the literature on this cardiomyopathy.

Isolated left ventricular apical hypoplasia is a very rare disease. There have been no more than 50 reports since its first description in 2004.¹ Diagnosis age ranges from three months to 66 years.²

In most patients, including our case, the condition is discovered incidentally. Because isolated left ventricular apical hypoplasia is very rare, initial echocardiographic diagnosis may appear as a dilated cardiomyopathy.¹ A wrapping right ventricle, a bulging ventricular septum toward the right ventricle, and an abnormal papillary muscle aroused the suspicion of this diagnosis and showed the need for a cardiac MRI.

There is no report in the literature of a single pattern regarding the ECG of patients with isolated left ventricular apical hypoplasia: the ECG may present right or left deviation. Poor R progression across the chest leads and left bundle block have also been described. In addition, non-sustained ventricular tachycardia and atrial tachycardia have been reported in these patients,³ as was also detected in our patient during a recent 24-hour Holter.

Clinical evolution may also vary from asymptomatic or mild clinical impairment to fatal arrhythmia. Therefore, the patient should be followed up to monitor the emergence of heart failure and arrhythmias.

To date, no clear cause for this disease has been established. The apical trabecular component, which is most universally present in normal and in malformed and incomplete ventricles, and which most readily differentiates right from left ventricles from a morphological standpoin,t is notably lacking in this disease. In most congenital left ventricle heart diseases, the apical component exists as an incomplete ventricle, even when the left ventricle sometimes lacks both the inlet and outlet components.⁴

We are not sure if this disease is part of some kind of genetic syndrome, but our patient also has arthrogryposis, as described by others.⁵ This association of cardiopathy and muscular dystrophy led us to hypothesize that this entity may be related to the Lamin A/C gene, which underlies the so-called laminopathies. One study has described a specific mutation in the Lamin A/C gene (p.Arg644Cys) associated with this cardiopathy.⁶ Mutations may be present in up to 40% of cases previously classified as idiopathic dilated cardiomyopathy.⁷ In this picture, geneticists and cardiologists have been working together and establishing more accurate diagnoses.

The Lamin A/C gene encodes Lamin A and Lamin C. Mutations in this gene may lead to cell and tissue fragility, mainly in tissues submitted to mechanical stress, like heart and muscle.⁸ A previous case report has described an association of arthrogryposis with this cardiomyopathy,⁵ with a mutation in the Lamin A/C gene (p.Arg644Cys), which is considered to be the potential genetic cause.⁶ This mutation is found not only in patients with cardiomyopathy, but also in patients with muscular and osteoarticular diseases⁹.

In the present case, no mutation in the Lamin A/C gene could be found; it is not surprising that, much like with most cardiomyopathies, more than one gene mutation may well be involved in causing this phenotype.

Isolated left ventricular apical hypoplasia is a very rare disease, with multiple clinical and electrocardiographic presentations. Close surveillance regarding heart failure and arrhytmias seems desirable. Although echocardiography may diagnose this entity, cardiac MRI is an invaluable tool in this diagnosis. Lamin A/C gene mutations alone may not account for this presentation.