When should I refer a patient to a genetic specialist for further eval

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Refer a patient to a genetic specialist if they meet the following criteria:

At least 2 first-degree or second-degree relatives diagnosed with breast cancer at younger than an average age of 50 years, or 3 relatives diagnosed at any age .
Families containing 1 relative with ovarian cancer at any age and, on the same side of the family, 1 first-degree relative (including the relative with ovarian cancer) or second-degree relative diagnosed with breast cancer at younger than age 50 years .
Families with a formal risk assessment indicating a 10% or greater chance of a gene mutation being present, or a greater than 8% risk of developing breast cancer in the next 10 years, or a 30% or greater lifetime risk .
Patients with high-risk features such as triple-negative breast cancer diagnosed under age 40, Jewish ancestry, sarcoma in a relative younger than 45, glioma or childhood adrenal cortical carcinomas, or complicated patterns of multiple cancers at a young age .
Presence of a very strong paternal family history, such as 4 relatives diagnosed younger than 60 years on the father's side .

In addition, direct referral is indicated if a high-risk predisposing gene mutation (e.g., BRCA1, BRCA2, TP53) has been identified .

When should I refer a patient to a genetic specialist for further evaluation of potential inherited cancer syndromes?