see Opitz-Kaveggia syndrome

FG is the acronym for the name of the first family in which a group of X-linked recessively transmitted abnormalities has been observed.

Five subtypes are described:

-        FGS1 or Opitz-Kaveggia syndrome [MIM 305 450]: mutation of the MED12 gene (Xq13.1)

-        FGS2 [MIM 300 321]: mutation of the FLNA gene (Xq28)

-        FGS3 [MIM 300 406]: mutation on Xp22.3

-        FGS4 [MIM 300 172]: mutation of the CASK gene (Xp11)

-        FGS5 [MIM 300 581]: mutation on Xq22.3