FRCOphth Part 1 Genetics

Begin with the molecular basics: DNA and RNA, transcription and translation, and the mutation types you need to tell apart, including missense, nonsense, frameshift, splice site and trinucleotide repeat expansion. Then the inheritance patterns, which carry most of the weight: autosomal dominant, autosomal recessive, X-linked recessive and dominant, and mitochondrial. Finish with the modifiers that complicate a pedigree, such as incomplete penetrance, variable expressivity, anticipation, mosaicism and genomic imprinting.

Retinoblastoma and the two-hit hypothesis are the standard worked example and worth knowing in detail. Beyond it, cover retinitis pigmentosa and its genetic heterogeneity, Leber hereditary optic neuropathy as the mitochondrial case, aniridia and PAX6, Marfan syndrome and fibrillin, the neurofibromatoses, albinism, and congenital colour vision defects as the X-linked recessive case. Learn each as an illustration of its inheritance pattern rather than as a free-standing fact, so one condition teaches you the shape of a whole class.

Practise pedigrees until reading one is mechanical, because that single skill answers a large share of the domain. Work exam-style SBAs that ask for the mode of inheritance or a recurrence risk, then use the referenced explanations to find the reasoning step you skipped rather than just checking whether the answer matched. Genetics is small enough to complete, so it is worth scheduling early and closing out rather than leaving open.