Non-invasive method for isolation and detection of fetal DNA

Abstract

A method of detecting the presence or absence of the fetal DNA sequence of interest in fetal DNA derived from a sample of peripheral blood obtained from a pregnant woman is described. The method involves obtaining a sample peripheral blood from a pregnant woman, treating the sample of peripheral blood such that the fetal DNA present in the fetal nucleated cells is made available for detection and detecting the presence or absence of the fetal DNA sequence of interest in the available fetal DNA. The proportion of fetal nucleated cells present in the sample of peripheral blood can be increased forming a sample enriched in fetal nucleated cells prior to the detection step. The fetal DNA sequence of interest can be detected by treating the peripheral blood sample such that fetal DNA present in the sample is made available for hybridization with a DNA probe and subsequently contacting the available fetal DNA with a DNA probe hybridizable to fetal DNA of interest under hybridization conditions. The presence or absence of hybridization between the DNA probe and the fetal DNA of interest is detected as an indication of the presence or absence of the fetal DNA of interest.

Description

RELATED APPLICATIONS [0001] This application is a continuation-in-part application of U.S. Ser. No. 07 / 772,689, filed on Oct. 7, 1991, which is a continuation-in-part application of U.S. Ser. No. 07 / 706,393, filed on May 28, 1991, now abandoned, which is a continuation-in-part of U.S. Ser. No. 07 / 436,057, filed on Nov. 13, 1989, now abandoned, all being entitled “Non-Invasive Method for Isolation and Detection of Fetal DNA” by Diana W. Bianchi. The contents of all of the forementioned applications are hereby expressly incorporated by reference.FUNDING [0002] Work described herein was supported by the National Institute of Health and Children's Hospital Medical Center. BACKGROUND [0003] A variety of fetal cell types—platelets, trophoblasts, erythrocytes and leucocytes—cross the placenta and circulate transiently within maternal blood (Schroder, J., J. Med. Genet. 12:230-242 (1975); Douglas G. W. et al., Am. J. Obstet. Gynec., 78:960-973 (1959)). There have been numerous reports of ef...

AI Technical Summary

Benefits of technology

[0006] The present invention is based, at least in part, on the discovery that fetal nucleated cells are present in the peripheral blood of a pregnant woman at a level which allows them to be useful in prenatal diagnostic methods. The method of the present invention is non-invasive because a peripheral blood sample from pregnant women, not fetal blood, is used as the source of the fetal DNA. The fetal DNA is derived from fetal nucleated cells present in the peripheral blood of a pregnant woman. The method of the present invention can be used to assess fetal characteristics (e.g. fetal sex and chromosomal abnormalities) or can be used to diagnose whether a fetus has a prenatal disease at an early stage of the gestational period. The non-invasive method of the present invention does not expose the fetus or mother to risks, e.g. infection, fetal injury, and miscarriage, associated with invasive methods such as amniocentesis.

Problems solved by technology

There have been numerous reports of efforts to separate fetal cells from maternal cells present in maternal blood, but none has been successful in isolating cells subsequently shown to contain fetal DNA.

Distinguishing fetal cells from maternal cells has not been successful for several reasons, including the small number of fetal cells in a maternal blood sample and the fact that morphological differences are slight (e.g., trophoblasts are the only fetal cells which can be distinguished from maternal cells by morphology alone).

However, although cells sorted in this manner have been said to be of fetal origin, based on analysis of cell surface antigens, morphology, or cytogenetic criteria, there has not been confirmation that the cells contain fetal DNA.

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