Inheritance patterns
For autosomal recessive, dominant, X-linked and mitochondrial disease, practise stating the recurrence risk and who can transmit. X-linked inheritance has no male-to-male transmission; mitochondrial inheritance is maternal only.
Our blueprint estimate puts 5–10 of the 200 questions in genetics, about 3.8% of the paper, spread across both papers. It is our estimate, not a figure published by the RCOG. A moderate share of the paper, and reliably examined.
5–10
of 200
8
in our syllabus map
human_structure
3 other areas
Genetics questions combine inheritance patterns with the screening and counselling decisions that follow from them. They are usually short, and they favour candidates who can apply a rule rather than recite one.
The 8 syllabus topics we map to Genetics for Part 1.
For autosomal recessive, dominant, X-linked and mitochondrial disease, practise stating the recurrence risk and who can transmit. X-linked inheritance has no male-to-male transmission; mitochondrial inheritance is maternal only.
A complete hydatidiform mole is androgenetic with no fetal tissue, whereas a partial mole is triploid with fetal tissue. Karyotype questions often hinge on exactly this distinction.
Genetics and Immunology for MRCOG Part 1 Gestational Trophoblastic Disease
Cell-free DNA testing analyses placental DNA and is a screening test, whatever its headline accuracy. A positive result is confirmed by invasive testing before any irreversible decision.
NICE DG31: Non-Invasive Prenatal Testing for Chromosomal Abnormalities Care After Non-Invasive Pre-Natal Testing
Imprinting and mosaicism explain results that a simple Mendelian rule cannot. Counselling questions test non-directive communication as much as the genetics.
Practise with small pedigrees: draw one for each inheritance pattern, state who is affected, and say the recurrence risk out loud. Keep a one-page table of the common chromosomal conditions with their mechanism and screening profile. Treat prenatal testing as a decision tree, with the screening step, the diagnostic step and the counselling that sits between them.
Part 1 is 200 single best answer questions across two papers with no negative marking, so an informed guess always beats a blank. Genetics shares its syllabus note with immunology, and its screening content overlaps with the statistics area, where sensitivity, specificity and predictive value turn up again.
Every question is original and written from published RCOG and NICE guidance, and every explanation cites the guideline it came from. Free: 5 days full access, then 50 questions. No card.
Published RCOG and NICE guidance summarised for revision, with the source cited on every page.
MRCOG AI is an independent educational tool. It is not affiliated with, endorsed by, or connected to the Royal College of Obstetricians and Gynaecologists (RCOG).