Fragile X syndrome inheritance follows a sex-linked dominant pattern. The mutation that causes this syndrome occurs in a gene on the X chromosome. For this reason, men who only have one X chromosome in their karyotype (46, XY) are more likely to suffer from this syndrome.
As can be seen in the image, there are three possibilities in the offspring if the father is healthy and the mother is a carrier of the mutation that causes Fragile X Syndrome:
- 25% of women will be carriers of the disease.
- 25% of men will be affected by Fragile X Syndrome.
- 50% of individuals will be healthy.
It should be noted that in women the random inactivation of one of the two X chromosomes occurs. This would also explain why, although it is a dominant inheritance, women can be carriers and not manifest the disease.
Read the full article on: Fragile X syndrome: what it is, causes, symptoms and treatment ( 32).
By Marta Barranquero Gómez B.Sc., M.Sc. (embryologist), Rut Gómez de Segura M.D. (gynecologist), Sergio Rogel Cayetano M.D. (gynecologist), Victoria Moliner BSc, MSc (embryologist) and Cristina Algarra Goosman B.Sc., M.Sc. (psychologist).
Last Update: 01/24/2022
