I knew a family of Marfan's from one of my jobs.

The women seem to have less obvious "symptoms" than the men.
The woman (Mother) I worked with had dilated aorta when pregnant only, and that was her only symptom which was silent.

Her daughter who is very tall -over 6ft, (mother is 5'8") had a ligament problem in her ankle. She twisted it, and it never seemed to heal from the sprain, and eventually a year later limping around, she went to an orthopedic surgeon, who said her ligament dissolved away after the injury (maybe due to the Marfan's genetic contribution). She had a reconstructive thing done where a partial tendon was taken from her thigh...and I don't know if that worked for her, as I retired and left that job.

There was also a Mystery Diagnosis show on Discovery once about a woman with "hidden" Marfan's. She was only diagnosed after one of her sons was tested. She was completely asymptomatic. But I wonder with your PN, if there is some connection involving the tendons, and collagen affecting the nerves etc?
I think it is worth following up upon, given that the gal I knew had a ligament totally dissolve away, and that created great pain for her. She was only 20 yrs old!