Haematological Disease

Question 1

Autosomal recessive maths

Answer 1

In autosomal recessive inheritance

• only homozygotes are affected
• males and females are equally likely to be affected
• not manifest in every generation - may ‘skip a generation’

If two heterozygote parents

• 25% chance of having an affected (homozygote) child
• 50% chance of having a carrier (heterozygote) child
• 25% chance of having an unaffected (i.e. genotypical) child

If one affected parent (i.e. homozygote for gene) and one unaffected (i.e. not a carrier or affected)

• all the children will be carriers

Autosomal recessive disorders are often metabolic in nature and are generally more life-threatening compared to autosomal dominant conditions