Dropped head syndrome as a manifestation of Charcot-Marie-Tooth disease type 4C.

ABSTRACT

Charcot Marie Tooth disease type 4C (CMT4C) is considered the most frequent autosomal recessive form of CMT worldwide, being described as an early-onset disorder with marked clinical heterogeneity. We report a CMT4C case associated with dropped head syndrome and predominant involvement of proximal muscles. An 11-year-old boy born to consanguineous parents presented with predominantly proximal muscle weakness with facial involvement, associated with dropped head and severe scoliosis. Symptoms started at the age of 3 years-old with frequent falls. Nerve conduction studies showed a sensorimotor demyelinating polyneuropathy. A comprehensive multigene next-generation sequencing panel for CMT revealed the homozygous pathogenic missense variant c.1969G > A (p.E657K) in SH3TC2 gene, confirming CMT4C diagnosis. The present report broadens the phenotype associated with CMT4C and raises the importance of considering early-onset inherited polyneuropathies in the differential diagnosis of patients with proximal muscle wasting associated with dropped head syndrome.