The classic forms of GBS and MFS and their subtypes constitute the GBS spectrum and overlapping syndromes, which share common clinical features, including a history of previous infection, a single-phase course, symmetry, cranial or limbs weakness, CSF albumin cell separation (high protein and normal cell count), AGAbs, and evidence of demyelinating neuropathy neurophysiology. This evidence concerns the gene ALB and Marfan syndrome.