Unusual Case of Facioscapulohumeral Dystrophy

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To the Editor:
Facioscapulohumeral dystrophy (FSHD) is the third most common muscular dystrophy after myotonic dystrophy and dystrophinopathies. It is an autosomal dominant disorder characterized by slowly progressive asymmetric muscle weakness involving the face, scapula, upper arm, lower leg, and hip girdle muscles.1 We report a 63-year-old man who presented with progressive asymmetric muscle weakness. His symptoms began at age 57 when he noticed that he would trip on curbs after he was in a motor vehicle accident, and over the next several years he was using crutches. In a span of 2 years, he became reliant on a wheelchair for ambulation outside his home. At age 62, he presented with fairly acute weakness of the left arm and leg and was evaluated for a stroke. At this time, magnetic resonance imaging of the brain was normal, and magnetic resonance imaging cervical spine revealed chronic, mild–moderate spinal cord stenosis at the level of C3-C6 without cord signal change that was unchanged from imaging performed 1 year ago. The patient denied any history of diplopia, dysphagia, shortness of breath, or bowel/bladder abnormalities. He was never on a statin. On examination, there was very mild weakness of the orbicularis oculi without any other facial weakness. There was atrophy of the forearm and thigh muscles but no myotonia. Right scapular winging was greater than left scapular winging. He was weaker in the left than in the right upper extremity. Most upper extremity muscle groups ranged 4s to 5-, with elbow extension as weak as 3 on the left. Notably, the deep and superficial finger flexors were 1/5 on the left and 3/5 on the right while the finger extensors, abductors, and abductor pollicis brevis were 4 + to 5. In the lower extremities, the most affected muscles were hip flexors (trace movement), knee extension (2/5), and ankle dorsiflexion (no movement). Sensation and coordination were intact and reflexes were symmetric. Electromyography/Nerve conduction study was first performed at age 62, which showed generalized myopathy without evidence of peripheral neuropathy. Creatine kinase was 1137 U/L. Genetic testing confirmed the diagnosis of FSHD based on a deletion on the 4q35A allele, resulting in a fragment size of 11 kb in the D4Z4 region (normal >38 kb). There was no mutation of the SMCHD1 gene. This case highlights some of the challenges in diagnosing FSHD. First, on initial presentation or during the course of their illness, patients with FSHD can present with relatively rapid progression weakness as our patient did on at least one occasion. Second, in a minority of patients, facial weakness is relatively or completely spared: our patient had very minimal facial involvement, despite profound extremity weakness. Last, a unique feature of our patient was the degree of finger flexion weakness relatively to other upper extremity muscle groups, a pattern that has not been well described in the literature. Our patient did have some classic examination findings of FSHD (scapular winging, an asymmetric pattern of weakness, predilection for tibialis anterior muscle), but these clues were initially overlooked, likely because of the unusual features and his older age of onset. This patient serves as a reminder of the value of a thorough systematic approach to the neuromuscular examination in all patients and that myopathies can present in a nonmyopathic fashion.

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