X-linked inheritance

📖 Full definition

Men (XY) have only one X: a recessive allele on this chromosome expresses directly, without counterbalance. Women (XX) must carry the allele on both X chromosomes. That is why some conditions (colour blindness, haemophilia A) affect men more often.

💡 Concrete example

Colour blindness is X-linked: ~8% of men are affected versus ~0.5% of women.

🔄 Synonyms

X-linked · sex-linked inheritance

🔗 See also

• Autosomal →
• Recessive gene →
• Mendelian →