The FGD1 gene provides instructions for making a protein that turns on activates another protein called Cdc42, which transmits signals that are important for various aspects of development before and after birth. FGD1 encodes a GEF that specifically activates , a member of the Ras homology family of the p21. Trials of have been effective to treat short stature in this disorder.
Mutations in the FGD1 gene are the only known genetic cause of Aarskog-Scott syndrome.
Mutations in the FGD1 gene lead to the production of an abnormally functioning protein. The characterization of the of FGD1 expression in mouse embryos has provided important clues to the understanding of the of Aarskog—Scott syndrome.
The cause of Aarskog-Scott syndrome in other affected individuals is unknown.
By activating Cdc42, FGD1 stimulates to form filopodia, cytoskeletal elements involved in cellular signaling, adhesion, and migration. Some may have mild learning and behavior problems, while others have normal intelligence. Other examinations or tests can help with diagnosis.
NextThis condition mainly affects males, although females may have mild features of the syndrome.
Other abnormalities in people with Aarskog—Scott syndrome include heart defects and a split in the upper lip with or without an opening in the roof of the mouth. Some males may have problems with fertility.
NextThey frequently have mild to moderate short stature during childhood, but their growth usually catches up with that of their peers during puberty.
Most males with Aarskog—Scott syndrome have a , in which the scrotum surrounds the penis instead of hanging below. The intellectual development of people with Aarskog—Scott syndrome varies widely.
NextThrough Cdc42, FGD1 protein also activates the JNK signaling cascade, a pathway that regulates cell growth, , and cellular differentiation.
These mutations disrupt Cdc42 signaling, leading to the wide variety of abnormalities that occur in people with Aarskog-Scott syndrome.
Only about 20 percent of people with this disorder have identifiable mutations in the FGD1 gene. Smith's Recognizable Patterns of Human Malformation 6th ed. Retrieved 18 June 2014.
These results suggest that FGD1 signaling may play a role in the biology of several different skeletal cell types including mesenchymal prechondrocytes, chondrocytes, and osteoblasts.