Frontotemporal lobar degeneration in a patient carrying a pathogenic PABPN1 expansion.

BACKGROUND

Expansions in PABPN1 cause oculopharyngeal muscular dystrophy (OPMD), a disorder classically characterized by ptosis, dysphagia, and proximal limb weakness. Cognitive impairment and frontotemporal dysfunction have been reported in selected patients with OPMD, but the relationship between heterozygous PABPN1 expansions and frontotemporal lobar degeneration (FTLD) remains uncertain.

CASE PRESENTATION: We report a 69-year-old man with progressive language-predominant cognitive decline and asymmetric left anterior temporal and frontoparietal atrophy who was found to carry a heterozygous pathogenic PABPN1 expansion [c.30_32dup, p.Ala11dup].

CONCLUSION

Because classical neuromuscular manifestations of OPMD were absent, this case is best interpreted as FTLD occurring in a patient carrying a pathogenic PABPN1 expansion rather than as definitive OPMD-related neurodegeneration.