pregnancy CMT1A pre-implanation diagnosis research

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Abstract from Mol Hum Reprod. 2003 Jul;9(7):429-35.

Preimplantation genetic diagnosis for Charcot-Marie-Tooth disease type

1A.

(in-vitro for non-genetic transmission of CMT1A to the next generation)

De Vos A, Sermon K, De Rijcke M, Goossens V, Henderix P, Van Ranst N,

Platteau P, Lissens W, Devroey P, Van Steirteghem A, Liebaers I.

Centre for Reproductive Medicine

Charcot-Marie-Tooth (CMT) disease is the 'common' name for a range of

hereditary peripheral neuropathies. CMT1 is the most common form and is

transmitted in an autosomal dominant manner. CMT1A maps to chromosome

17p11.2 and is caused, in the majority of cases, by a 1.5 Mb DNA

duplication, that includes the peripheral myelin protein 22 (PMP) gene.

This paper reports on preimplantation genetic diagnosis (PGD) for CMT1A

in five couples.

The CMT1A duplication was detected by fluorescent PCR analysis using

polymorphic (CA)n markers localized within the duplication. Single-cell

PCR on blastomeres allowed genetic analysis of embryos obtained after

ICSI. Only healthy unaffected embryos

were transferred to the uterus. PCR experiments with single

EBV-transformed lymphoblasts or with research blastomeres allowed the

evaluation of amplification efficiencies, as well as contamination and

allele drop-out (ADO) rates for each PCR protocol. Three simplex PCR

protocols (using one primer pair) and two duplex PCR protocols (using

two primer pairs) were developed for CMT1A. Additionally, a protocol

using all three primer pairs in triplex was also established. Thirteen

clinical ICSI-PGD cycles were performed for five couples (12 simplex PCR

cycles and one duplex PCR cycle), resulting in seven embryo transfers.

Three singleton pregnancies ensued in two couples and three healthy

babies were delivered. This report describes different fluorescent

PCR-based tests which allow efficient and accurate single-cell level

detection of the CMT1A duplication. On the basis of the presence of the

healthy allele of the affected parent-to-be (and/or absence of the

affected one), healthy embryos can be selected for transfer. The assays

are suitable for PGD for other couples who present with the same CMT1A

duplication [depending on their informativity for the (CA)n markers

available] as described here.