D3.2.12—Haemophilia
Haemophilia is an X-linked recessive disorder, so carrier females can have affected sons and affected males pass alleles through daughters.
- Syllabus
- First assessment 2025
- Objective
- D3.2.12
- Level
- SL
Exam analysis
Chance of appearing5%of analysed past papers
Latest appearanceMay 2022
Most common paperPaper2
Typical marks1–3
Common command terms
- Identify
- Deduce
- Explain
- Outline
- State
- Predict
Recent exam appearances
May 2022Paper2 ["SL"] · TZ26(b)[ 3 ]D3.2.12—Haemophilia
May 2022Paper2 ["SL"] · TZ14(b)[ 3 ]D3.2.12—Haemophilia
May 2022Paper2 ["SL"] · TZ14(a)[ 1 ]D3.2.12—Haemophilia
May 2014Paper2 ["SL"] · TZ24(c)[ 2 ]D3.2.12—Haemophilia
May 2014Paper2 ["SL"] · TZ24(b)[ 2 ]D3.2.12—Haemophilia
Practice this objective
Coverage 2010–2022 · Updated 16 Jul 2026
Concept essentials
- Males express an X-linked recessive allele if it is on their single X chromosome.
- Heterozygous females are usually carriers for haemophilia.
- Affected fathers pass their X chromosome to daughters, not sons.