A panel of 399 individuals from 24 kindreds with facioscapulohumeral muscular dystrophy (FSHD) has been established for genetic linkage studies. A previous suggestion of linkage on the distal long arm of chromosome 14 to the locus (IGHG) for the constant region of the heavy chain of IgG immunoglobulin was tested from serum Gm allotypes and from DNA analysis using an IGHG DNA probe. After applying an age-dependent weighting for presently unaffected but at risk individuals close linkage between the IGHG and FSHD loci was excluded.