From the Research
Sex-linked inheritance refers to the pattern of inheritance for genes located on the sex chromosomes (X and Y), where most sex-linked traits are found on the X chromosome and are called X-linked traits, with males expressing recessive X-linked traits more frequently than females. In humans, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY), creating a distinctive inheritance pattern for traits determined by genes on these chromosomes.
- The X chromosome carries many genes that are responsible for various traits and conditions, including X-linked recessive disorders such as hemophilia, color blindness, and Duchenne muscular dystrophy 1, 2.
- When a father passes an X-linked trait to his children, all daughters will inherit it (as they receive his X chromosome), but none of his sons will (as they receive his Y chromosome) 3.
- Mothers with an X-linked trait have a 50% chance of passing it to each child, regardless of sex, creating distinctive family pedigrees where affected males are connected through carrier females, and fathers cannot pass X-linked recessive conditions to their sons 2, 3.
- Y-linked inheritance is much rarer since the Y chromosome contains fewer genes, primarily those involved in male development and fertility 4.
- Recent studies have highlighted the importance of genetic counseling and testing in adolescents with genetic conditions, including sex-linked inheritance disorders, to improve their understanding and adaptation to their condition 5.
- The most recent and highest quality study on the topic of sex-linked inheritance is from 2022, which emphasizes the need for tailored genetic counseling services for adolescents with genetic conditions, including those with sex-linked inheritance disorders 5.