Objective: Presentation of a novel case, involving the design and implementation of preimplantation genetic diagnosis (PGD) for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
Methods: The disease-causing mutation, c.459C>T (R153C) in exon 4 of the Notch3 gene, was previously identified in the affected father. The family already had a pregnancy termination following prenatal diagnosis and chose to undergo PGD. A PGD protocol was designed to include informative, linked short tandem repeat (STR) markers and an intragenic single nucleotide polymorphism (SNP), coupled to mutation identification. Biopsy was performed at day 3 and blastocysts were transferred on day 5 after fertilization. Standard prenatal diagnosis procedures were employed to confirm the PGD results.
Results: One blastomere was removed at day 3 from each of eight embryos. Detection of the c.459C>TNotch3 mutation, coupled to informative polymorphic markers, unambiguously identified three unaffected embryos. Blastocyst transfer resulted in a singleton pregnancy and subsequent prenatal diagnosis confirmed that the fetus was disease-free.
Conclusions: Given the dominant, highly penetrant and potentially serious effects of Notch3 mutations, PGD for CADASIL may be considered and implemented as a reproductive option, following proper genetic counseling.