# FLOW KARYOTYPING: OPTIMIZATION AND CLINICAL EVALUATION

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 1994 · $540,805

## Abstract

The overall objective of this project is to develop and evaluate improved
analytical cytologic techniques for prenatal detection of disease-linked
cytogenetic abnormalities.  Emphasis will be on a) improving the speed and
sensitivity with which the loss or gain of chromosomal DNA can be detected
and quantified during analysis of metaphase chromosomes, b) detection of
common cytogenetic abnormalities in interphase cells and c) developing
techniques for cytogenetic analysis using fetal cells isolated from
maternal blood.  These objectives will be pursued by:

1) Applying bivariate flow karyotyping to quantification of the extent of
chromosome deletions and duplications as small as 1 Mb.  Effort during this
project period will be devoted to further increasing the sensitivity of the
technique and applying it in a series of collaborative studies to
characterize subtle structural aberrations of clinical or molecular
biological importance.

2) Optimizing fluorescence in situ hybridization with chromosome specific
probes for reliable detection and characterization of numerical aberrations
involving chromosomes 21, 18, 13, x and y; segmental duplications
(initially 21q22.3 for Down syndrome) and deletions (initially 15q11-13 for
Prader-Willi syndrome) in metaphase spreads and in interphase nuclei.

3) Developing chromosome-specific probes to support the fluorescence
hybridization studies.  Whole-chromosome DNA and ssRNA probes depleted in
repetitive sequences will be generated from chromosome-specific cosmid
libraries.  Composite probes for 21q22.3, 15q11-13 and elsewhere will be
generated by starting with "seed" probes already mapped to these regions
and "walking" outward in chromosome-specific cosmid libraries to expand the
regions covered by the composite probes.

4) Continuing efforts to isolate fetal cells from maternal blood for
interphase cytogenetic analysis.  Specific projects include:  a)
determination of the gestational age within the first trimester at which
the fetal cells are present at highest frequency in maternal
blood,b)determination of the origin of the fetal cells (e.g. leukocytes or
cytotrophoblasts) and c) development of procedures for enrichment of the
fetal cells.

## Key facts

- **NIH application ID:** 2197508
- **Project number:** 5R01HD017665-13
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **SAM.gov UEI:** KMH5K9V7S518
- **Principal Investigator:** JOE W. GRAY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $540,805
- **Award type:** 5
- **Project period:** 1991-07-01 → 1994-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2197508

## Citation

> US National Institutes of Health, RePORTER application 2197508, FLOW KARYOTYPING: OPTIMIZATION AND CLINICAL EVALUATION (5R01HD017665-13). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2197508. Licensed CC0.

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