Genetic carrier screening — structured oral station (12 minutes)

Opening prompt — "Tell me what you would say to them."

Model response: ^[1]

• "Carrier screening is a blood test that tells us whether you carry a gene change that, if your partner carries the same one, could cause a serious condition in a child. Most affected children are born to couples with no family history, which is why we offer it to everyone."
• "The standard panel looks at three conditions: cystic fibrosis, spinal muscular atrophy and fragile X. Carrier frequencies are about 1 in 25, 1 in 40 and 1 in 250 women respectively."^[1]
• "We do it before you conceive, because a result known now keeps every option open — including IVF to select unaffected embryos. I would test the woman first, and her partner only if she is a carrier."^[1]

Probe 1 — "Why before conception? Why not at the booking visit?"

• "Because the options change. Before conception, a positive result lets a couple choose IVF with pre-implantation genetic testing, donor gametes, or not to conceive. Once pregnant — especially past the first trimester — we are left with prenatal diagnosis and a possible termination, which is a narrower, harder set of choices."^[1]

Probe 2 — "She asks: if the test is negative, does that mean no risk?"

• "No — and this is important. A negative screen greatly reduces the risk but does not bring it to zero, because the panel detects the common variants but not every rare one. There is always a residual risk, and I would tell her that."^[1][6]

Probe 3 — "The result comes back: both of them are carriers of spinal muscular atrophy. What do you do?"

• "Refer to clinical genetics, and lay out the reproductive options, without directing them to one: accept the one-in-four risk; natural conception with prenatal diagnosis and the option of termination; IVF with pre-implantation genetic testing; donor gametes; or adoption. The choice is theirs, supported by counselling on what SMA means for a child."^[1]

Probe 4 — "Now her own result is a fragile X premutation. Does that change anything?"

• "Yes — fragile X is different. As well as the reproductive risk to a future child, a premutation has implications for her: an increased risk of fragile-X-associated primary ovarian insufficiency, with reduced fertility and earlier menopause, and her relatives may carry it too. We offer cascade testing of the family and discuss her ovarian reserve."^[9]

Probe 5 — "They are overwhelmed. Counsel them."

This is a scored domain. Demonstrate it out loud: ^[1]

• Move to their eye level, use their names, validate the overwhelm: "It is a lot to take in, and we will go at your pace."
• Brief plainly: "Being a carrier is not an illness — it just means we plan. You have options, and our genetics team will walk through every one with you. There is no rush and no right answer."
• Offer a written summary, a follow-up appointment, and the genetic counsellor contact.^[1]