a recognized HDSA Center of Excellence, our goal is to provide
comprehensive clinical services to our patients and their family
members in the New York City Metropolitan area. One aspect of those
clinical services includes genetic counseling and testing services.
mission of the genetic counseling and testing program is to provide
an environment with the necessary support and information such
that individuals may make an informed decision regarding presymptomatic
genetic testing for Huntington's disease, confirmatory genetic testing for people with symptoms and preimplantation diagnosis and in-vitro fertilization services for family planning. In addition, it is our
aim to facilitate the follow-up care of individuals who complete
the testing process by referring them to the resources available
in the Huntington's Disease Center at Columbia University.
Karen Marder, MD, MPH
Louis, MD, MSc
Steven Frucht, MD
Mark Groves, MD
Deborah Zeck Thorne, LCSW
Jennifer Williamson-Catania, MS
Wendy Chung, MD, PhD
For more information regarding genetic testing for Huntington's
Disease contact Jennifer Williamson, MS, Genetic Counselor at (212)305-4655
the passing of characteristics from parent to child by genes.
the basic units of heredity passed from a parent to a child.
The genes determine the characteristics of each person. For example,
there are genes that affect eye color, hair color and blood type.
People differ in these characteristics because their genes are
different. There are approximately 100,000 genes that make up
the characteristics of a person.
the packages that carry the genes. Chromosomes are found in every
cell of the body and occur in pairs. One copy of each chromosome
is inherited from a person's mother and a second copy from the
father. Therefore, a person has 2 copies of each chromosome and
2 copies of each gene, one gene on each chromosome. There are many
genes on each chromosome.
DNA code is
the basic unit of chromosome information that determines the
makeup of the genes. This chemical code makes a gene, and any
changes to this code may also change how the gene works. DNA
consists of 4 small elements called bases. These bases are named
adenine (A), guanine (G), thymine (T), and cytosine (C).
gene that causes HD has an area in which 3 bases (CAG) are repeated
1 2 3 4 5 6 7 8 9 10 11 12
The gene for
Huntington's disease is located on chromosome number 4. The gene
causing HD has 40 or more CAG repeats.
|No. of CAG Repeats
||Normal range; individual will not develop HD
||Individual will not develop HD, but the next generation is
||Some, but not all, individuals will develop HD; next generation
is also at risk
||Individual will develop HD
testing analyzes the number of CAG repeats on the gene inherited
from the individual's mother and the gene inherited from the individual's
father. A small blood sample is required for the genetic test.