The following is a summary of “Characteristics of the muscle involvement along the disease progression in a large cohort of oculopharyngodistal myopathy compared to oculopharyngeal muscular dystrophy,” published in the August 2023 issue of Neurology by Eura et al.

Oculopharyngodistal myopathy (OPDM) is an inherited muscle disorder caused by mutations in 4 genes: LRP12, GIPC1, NOTCH2NLC, or RILPL1. It causes weakness in the eyes, throat, and limbs. The progression of the disease varies among individuals. Researchers conducted a retrospective study to identify muscle imaging indicators for OPDM, contrasting with clinically akin oculopharyngeal muscular dystrophy (OPMD).

They analyzed axial muscle CT and/or T1-weighted MRI data from 54 genetically confirmed OPDM patients (OPDM_LRP12; n=43, OPDM_GIPC1; n=6, OPDM_NOTCH2NLC; n=5) and 57 with OPMD. Each muscle’s fat infiltration degree was scored using the modified Mercuri score. Hierarchical clustering analyses were conducted to categorize patients and deduce progression patterns.

The results showed a consistent muscle distribution pattern emerged across all OPDM subtypes: initial involvement of soleus and medial gastrocnemius, succeeded by tibialis anterior and extensor digitorum longus. Distinguishing between OPDM and OPMD, severe impairment in gluteus medius/minimus and adductor magnus pointed towards OPMD.

Investigators concluded a diagnostic muscle involvement pattern in OPDM that can help with diagnosis and intervention.

Source: link.springer.com/article/10.1007/s00415-023-11906-9