The FLNA gene is a member of the Filamin (FLN) family, which includes three members: filamin A, filamin B and filamin C.  The encoded filamin proteins show 60–80% homology over their entire sequence, except for the two hinge regions.  These three proteins are widely expressed during development.  The FLNA gene encodes an actin-binding protein called filamin A, which links actin filaments to membrane glycoproteins and crosslinks actin filaments.  It plays a role in modeling the cytoskeleton allowing cell shape changes and migration.  Filamin A also interacts with transmembrane receptor complexes, integrins, and second messengers.  Defects in this protein have been associated with genetic diseases including FG syndrome, frontometaphyseal dysplasia, intestinal pseudo-obstruction, Melnick-Needles syndrome, otopalatodigital syndrome type 1 and 2, periventricular heterotopia, and X-linked cardiac valvular dysplasia.

The FLNA gene has 46 coding exons spanning approximately 26 kb on the X chromosome.  This gene has two transcript variants encoding different isoforms.  The encoded protein comprises 2647 amino acids with a molecular mass of about 280 kDa.  Mutations in this gene have been identified in patients with several syndromes including FG syndrome, frontometaphyseal dysplasia, intestinal pseudo-obstruction, Melnick-Needles syndrome, otopalatodigital syndrome type 1, otopalatodigital syndrome type 2, periventricular heterotopia, and X-linked cardiac valvular dysplasia.  Each of these mutations causes specific defects in the filamin A protein resulting inFLNA-related disorders.  Frontometaphyseal dysplasia and Melnick-Needles syndrome are caused by "gain-of-function" mutations, which cause an increase in the activity of the filamin A protein or alter its function. a new function.  Mutations in exons 3, 4, and 5 have been found in patients with otopalatodigital syndrome type 2, and mutations in exons 11 and 29 have been identified in patients with similar but more severe symptoms.