The prenatal exclusion test for Huntington's disease: experience in the west of Scotland, 1986-1993.

Abstract

Information about the prenatal exclusion test for Huntington's disease (HD) The families Nine of the 10 couples who subsequently underwent exclusion testing were married and one couple married between their first and second tests. All couples were specifically counselled about the exclusion test at least once in the preconception period by the same geneticist and on a second occasion by the same or another geneticist. Four consultands had the exclusion test explained on three occasions before undergoing chorionic villus sampling (CVS). In addition to receiving oral explanations, consultands were give a leaflet prepared by the United Kingdom Association to Combat Huntington's Disease, which gives details on the working of both presymptomatic and prenatal exclusion tests.Details of the families and exclusion test outcomes are given in the table. It is notable that in nine out of 10 families, the mother was at 50% risk of being an HD gene carrier. As expected, the consultands were either primiparous or of low parity and the mean maternal age of 29 years was increased in keeping with an often stated preference to defer having children until it could be shown that consultands had a low chance of transmitting the

New tools for preimplantation genetic diagnosis of Huntington's disease and their clinical applications

“…19 -21 In most reported cases, couples went ahead with the TOP. Tolmie et al reported 22 the lowest rate of declining TOP after an unfavourable exclusion test (three out of nine), which also raises the problem of the child's right not to know since, if the parent develops the disease, the child is at high risk of being affected. 7 For all other reports, the TOP uptake was close to 100%.…”

Prenatal testing for Huntington's disease: a European collaborative study

“…Tolmie described a group of UK families who had difficulty with their decision to terminate an at risk pregnancy following exclusion testing. 16 Three out of nine high-risk pregnancies were continued. Clarke 17 demonstrated the problems associated with cases where an unfavourable result is produced, but the pregnancy continues.…”

Preimplantation genetic diagnosis for Huntington's disease with exclusion testing

“…17 An important objection to exclusion testing is that the highest possible risk for the fetus is 50%. This is sometimes difficult to accept as reported by Tolmie et al 18 In a series of 13 prenatal exclusion tests, four tested at low risk, and nine tested at high risk. Of these nine patients, three declined TOP, although all three patients had intended to go ahead with the TOP if an unfavourable result were obtained after PND.…”