Porphyria neuropathy is it symmetrical or asymmetrical?

porphyria neuropathy is it symmetrical or asymmetrical ?
And sir as it’s axonal neuropathy, thn why motor involvement is predominant than sensory ?

Porphyric neuropathy (PN) is a motor-predominant axonal neuropathy that begins symmetrically in the upper extremities, followed by lower-extremity involvement. Proximal muscles are more often affected, and PN can progress rapidly to quadriparesis and respiratory involvement that can be fatal if untreated.
As porphyric neuropathy is fundamentally an axonal neuropathy with predominant motor nerve dysfunction, electrodiagnostic findings typically support this pattern of neuropathy. Nerve conduction studies (NCS) during acute attacks show reductions in compound motor unit action potential (CMAP) with relatively preserved conduction velocities. Conduction abnormalities of sensory nerves are sometimes demonstrated but are less common than motor nerves. In later stages, when muscle weakness is more prominent, NCS may show progressive reductions in CMAP amplitudes. Thank you.