Is Aarskog-Scott Syndrome hereditary?

TL;DR: Aarskog-Scott syndrome is a hereditary condition primarily caused by mutations in the FGD1 gene, which follows an X-linked recessive inheritance pattern. While it is strongly genetic, some cases arise from de novo mutations, meaning the condition occurs for the first time in an individual without a prior family history.

Is Aarskog-Scott syndrome hereditary?

Yes, Aarskog-Scott syndrome is a hereditary condition. In clinical genetics, we distinguish between "genetic" (caused by a change in DNA) and "hereditary" (passed from parent to child). Because Aarskog-Scott syndrome is caused by a mutation in the FGD1 gene on the X chromosome, it is inherited in an X-linked recessive manner. This means that while it is always genetic, it is not always inherited from a parent; it can occur spontaneously.

How is Aarskog-Scott syndrome passed down?

The inheritance of Aarskog-Scott syndrome depends on the biological sex of the parent and child:

• Mothers who are carriers: Have a 50% chance of passing the FGD1 mutation to each son (who will be affected) and a 50% chance of passing it to each daughter (who will be a carrier).


• Affected fathers: Will pass the mutation to all of their daughters (who will be carriers) but will not pass it to their sons, as fathers pass their Y chromosome to sons.


• De novo mutations: Approximately 20–30% of cases are estimated to be de novo, meaning the mutation occurred spontaneously in the affected individual’s germ cells or early development.

Is genetic testing available for Aarskog-Scott syndrome?

Molecular genetic testing for Aarskog-Scott syndrome is available via FGD1 gene sequencing. We recommend testing for individuals presenting with classic physical features, such as hypertelorism, shawl scrotum, and brachydactyly. Genetic counseling is vital for families, as it helps clarify the recurrence risk, explains carrier status for female relatives, and discusses options like prenatal diagnosis or preimplantation genetic testing (PGT) for those planning future pregnancies.

Next steps

• Consult with a board-certified clinical geneticist to discuss individual recurrence risks.


• Connect with the Aarskog-Scott syndrome community at DiseaseMaps.org to share experiences with others navigating this rare diagnosis.


• Request a referral for genetic counseling before planning a pregnancy to understand reproductive options.


• Review your family history to identify other potentially affected male relatives who may have been undiagnosed.

Medical disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Aarskog syndrome.


• Orphanet: Aarskog-Scott syndrome (ORPHA:10).


• OMIM (Online Mendelian Inheritance in Man): FGD1 gene entry (#305400).