2 Neuroscience2.9 Genetics
2.9.9 Clinical psychiatric genetics
2 min read
Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic for exams from January 2027.
When genetics can help
A clinical genetic assessment is most useful when psychiatric symptoms come with developmental delay, intellectual disability, congenital anomalies (physical differences present from birth), unusual neurological findings or a family history that suggests a genetic cause.
A genetic diagnosis can clarify prognosis, surveillance and recurrence risk. It will not predict every symptom, and it does not replace the person's clinical formulation.
Referral links the treating team with clinical genetics and genomic laboratory services. The choice of test depends on the phenotype (the person's observable features), the family history and the relevant national pathways.
Counselling and testing
Situation | What to discuss |
|---|---|
Before testing | Possible results, the limits of the test, consent and what results mean for relatives |
Pathogenic result | How well it fits the person's features, inheritance, penetrance and possible family testing |
Uncertain variant | The uncertainty remains. It is not automatically a diagnosis |
Negative result | Genes may still contribute even though the test found no explanation |
Reproductive planning | The recurrence risk for that specific condition and the testing choices available |
Prenatal screening estimates risk. Diagnostic testing answers a defined chromosomal or molecular question. It still cannot forecast an unborn child's full psychiatric outcome.
Genetic counselling helps people make informed choices. It does not direct reproductive decisions or assume that relatives want predictive information.
Deoxyribonucleic acid (DNA) banks store samples for future testing or research. Consent should cover access, future use, recontact and any limits on withdrawal.
Polygenic risk scores add together many variants, each with a small effect. Routine use in psychiatry is limited by calibration (whether predicted risk matches the risk actually seen), poor portability across ancestries and uncertain clinical benefit.
A high polygenic score is not a diagnosis or a certainty of illness. A low score does not rule illness out.
Confidentiality matters because one person's result can reveal information about their relatives as well as themselves.