Medical Genetics
Autosomal Dominant: Myotonic Dystrophy
Genes are inherited from our biological parents in specific ways. One of the basic patterns of inheritance of our genes is called autosomal dominant inheritance.
What is autosomal dominant inheritance?
Autosomal dominant inheritance means that the gene is located on one of the autosomes (chromosome pairs 1 through 22). This means that males and females are equally affected, and "dominant" means that only one gene is necessary to have the trait. When a parent has a dominant trait, there is a 50 percent chance that any child they have will also inherit the trait:
There are four possible combinations in the children. Two of the four, or 50 percent, have inherited the trait. The other 50 percent have not inherited the trait. These four combinations are possible every time a pregnancy occurs between these two individuals. The gender of the children (whether they are sons or daughters) does not matter. The chance is 50/50 for each pregnancy.
What is myotonic dystrophy?
An example of an autosomal dominant condition is myotonic dystrophy. Myotonic dystrophy is an inherited disorder that causes muscle weakness and myotonia (inability of muscles to relax after use), which becomes more severe over time. Specific problems in other systems of the body can also occur. Myotonic dystrophy is known as an extremely variable condition. This means the severity varies (some people are mildly affected; others are very severely affected), which systems of the body it affects can vary, and at what age the disease starts can vary, even in the same family. This is a characteristic of dominant traits: they can have “"variable expression." Most families know that there is a dominant trait or disorder in their family, because it is passed from parent to child and can be seen in many generations. It is important to remember that with autosomal dominant inheritance, if a person does not have the trait, they cannot pass it on.
Click here to view the
Online Resources page of this Web.
Contact information:
Raymond Lewandowski, MD
Medical Director, GeneticistOfelia Rivera
Office ManagerDeborah Dansby
Sonographer SupervisorDenise Dominguez
Valley SupervisorAndrea Ramirez
Senior Genetic CounselorCPSST - Driscoll Genetics Services
5920 Saratoga Blvd. 540
Corpus Christi, Texas 78414
Phone: (361) 694-1600 or (361) 985-6600
Fax: (361) 985-6603
Hours 8-5 pmCPSST - Driscoll Genetics Services -Brownsville
1096 Los Ebanos, Suite B
Brownsville, TX 78520
Phone: (956) 544-5663
Fax: (956) 544-7386CPSST - Driscoll Genetics Services - Harlingen
2220 Haine Dr., Suite #46
Harlingen, TX 78550
Phone: (956) 428-0897
Fax: (956) 428-0899CPSST - Driscoll Genetics Services - McAllen
1910 S. First St., Suite #500
McAllen, TX 78501
Phone: (956) 686-0503
Fax: (956) 668-0503
Hours: 8 – 5 Monday – Friday
Statement of Compliance
Voted Best Place to Work in 2006 and 2007 | Ways to Give | Contact Us
Copyright © Driscoll Children's Hospital 2008
Corpus Christi, Texas
Live website tracking by Visistat
