NPPB and Abnormal autonomic nervous system physiology: Active, not recruitingPrimary outcome measures: response rate to TUDCA (based in mBMI reduction <10%, change in neurologic impairment score-lower limbs (NIS-LL) <2, and NT-proBNP <30% (or <300 pg/ml)Secondary outcome measures: treatment-emergent adverse events, doxycycline PK, response in autonomic dysfunction, neuropathy and visceral organ involvement, incidence of patients discontinuing from study due to clinical or laboratory adverse events