Left ventricular noncompaction cardiomyopathy in Duchenne muscular dystrophy carriers

Newborn screening for Duchenne muscular dystrophy-early detection and diagnostic algorithm for female carriers of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the most common pediatric-onset form of muscular dystrophy, occurring in 1 in 5,000 live male births. DMD is a multi-system disease resulting in muscle weakness with progressive deterioration of skeletal, heart, and smooth muscle, and learning disabilities. Pathogenic/likely pathogenic (P/LP) variants in the DMD gene, which encodes dystrophin protein, cause dystrophinopathy. All males with a P/LP variant in the X-linked DMD gene are expected to be affected. Two to 20% of female heterozygotes with a P/LP variant develop symptoms of dystrophinopathy ranging from mild muscle weakness to significant disability similar to Becker muscular dystrophy. Recently, with improvements in therapies and testing methodology, there is stronger evidence supporting newborn screening (NBS) for DMD for males and females because females may also develop symptoms. A consented pilot study to screen newborns for DMD was initiated in New York State (NYS) and conducted from 2019 to 2021. The identification of female carriers and the realization of the subsequent uncertainty of providers concerning follow-up during the pilot led to the development of algorithms for screening and diagnosis of carrier females, including both NBS and cascade molecular testing of family members.

Non-compaction cardiomyopathy, Becker muscular dystrophy, neuropathy and recurrent syncope

We present the case of a 50-year-old man presenting with new heart failure symptoms. He had no evidence of any ischaemic cardiomyopathy, however, further cardiac imaging showed a left ventricular non-compaction cardiomyopathy. He was noted to have muscular weakness and an exhaustive search for associated comorbidities yielded a diagnosis of Becker muscular dystrophy. In this report, we review the pathophysiology, comorbidities and diagnostic workup in patients presenting with left ventricular non-compaction in the context of dystrophinopathy. Ultimately, we suggest the consideration of rare cardiomyopathies in all patients presenting with neuromuscular syndromes and vice versa.