Testing of a person (the person tested) for the detection of a single gene variant for segregation analysis in relation to another person (the patient), if: the patient has a known phenotype of a suspected monogenic condition; and a service described in item 73358 or 73360 has identified a potentially causative variant for the patient; and the person tested is a biological parent or other biological relative of the patient; and a sample from the person tested has not previously been tested in relation to the patient for a service to which item 73359 applies; and the results of the testing of the person tested for this service are made available for the purpose of providing the detection for the patient; and the detection is: requested by a consultant physician practising as a clinical geneticist; or requested by a consultant physician practising as a specialist paediatrician, following consultation with a clinical geneticist; and the detection is not performed in conjunction with item 73361 or 73362 Applicable only once per variant per lifetime