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Consent for minor procedures including amniocentesis and CVS has been a requirement for decades and needs no repetition. However, the advent of chromosomal microarrays (see Chapter 13) and whole‐exome sequencing for prenatal diagnosis (see Chapter 14) requires additional explanations and caveats. Informed consent for these two technologies is focused on the potential results, not sampling risks and procedures. The specific issues primarily involve the interpretation of results, their significance, the small possibility of uncertain findings, test limitations, and incidental results.

Chromosomal microarray testing adds up to 6–10 percent to a prenatal diagnosis result (see Chapter 13) beyond the 8–10 percent for routine karyotyping, and whole‐exome sequencing when done after the ultrasound discovery of fetal structural abnormality adds an additional 6.2–80 percent.^{691, 704–708} This absurd range reflects very small case series, varying indications, and the presence of single or multiple fetal abnormalities. A more likely detection range would be between 8.5 and 32 percent.^{707, 708}

Prenatal diagnosis using whole‐exome sequencing (see Chapter 14) is primarily focused on pregnancies in which fetal structural abnormality has been observed. A much less frequent indication would be a recent or late diagnosis of a parent with a likely monogenic disorder characterized by genetic heterogeneity. No matter the indication, the informed consent obtained incorporates and extends current practice for chromosomal microarray tests. The decision to offer whole‐exome sequencing will almost inevitably come on the heels of the detection of fetal abnormality and in an atmosphere of tension and anxiety. Any center offering whole‐exome sequencing will have, of necessity, established their informed consent procedure. The following list of pointers are likely to find common ground:

1 Pre‐ and postgenetic counseling by a geneticist or genetic counselor is a prerequisite, with strict adherence to ethical standards.⁷⁰⁹, ⁷¹⁰

2 Both parents should be in attendance.

3 Explanations should use simple language, no jargon, and be in the language of the parents (with an interpreter, if needed).

4 The details of the fetal abnormality, effect on a child (pain; disability), a progressive disorder or not, and life expectancy.

5 The use of targeted sequencing, trios, and gene panels will need explanations, including the reason and need for prior or simultaneous chromosomal microarrays.

6 The time needed to obtain a result.

7 The likely detection rate and the limitations of whole‐exome sequencing (e.g. repeat expansion disorder; mosaicism).

8 The occurrence of false positives, false negatives, or error.

9 The unexpected discovery of nonpaternity or consanguinity.

10 The detection of a variant of unknown significance.⁷⁰⁹

11 A “secondary finding”⁷¹¹–⁷¹⁴ unrelated to the original purpose of the analysis.

12 The opportunity for the parents to opt out of receiving “secondary findings”⁷¹⁵ which they should understand may have personal important health implications.

13 The choice to refuse testing.