There are other less common symptoms, such as some cases of a high frequency hearing loss. Abnormalities of blood vessels in the back of the eye are sometimes present, but they rarely lead to visual problems. Inheritance is the means of transmission of DNA, and therefore characteristics and traits, from parent to child. Chromosomes are the vehicles for those transmissions. Humans have 23 pair of chromosomes in their cells.
Children inherit one member of each equivalent pair of chromosomes from each parent.
Most FSHD cases occur due to a DNA mutation on one member of the chromosome 4 pair. There are also some occasional instances where symptoms are compatible with the FSHD syndrome, but where genetic studies exclude chromosome 4 as the location of the FSHD mutation. The chromosomal locations of these mutations are unknown. Chromosome 4 is an autosome. When a person inherits a chromosome 4 with the FSHD mutation, symptoms of FSHD develop.