Genetic Counselor

A Genetic Counselor is a health professional with specialized graduate degrees and experience in areas of medical genetics and counseling.  Their required qualification is a Master’s Degree. Genetic Counselors need to be educated in genetics, psychosocial theory, ethics, counseling, and clinical training.

On the job, a genetic counselor will work with patients and families in hospitals or in a private practice.  A commercial genetic counselor will work with biotech companies that design and sell genetic tests.  Other fields that genetic counselors work in include diagnostic labs and research.

Inheritance of Leigh's Disease

Leigh’s disease can be inherited through a number of ways.  The most common form of inheritance is autosomal recessive transmission.  This is when both parents carry the gene, so each child has a twenty-five percent chance of being affected with Leigh’s disease.  This is a genetic transmission.  However, another form of inheritance is X linked transmission.  If the mother carries this disease, male children can inherited it and female children may become carriers.  This transmission is chromosomal.

Genotypes - Autosomal Recessive and X Linked

Genotypes for parents can be...

1. RR - Unaffected 
2. Rr - Carrier; Unaffected by Leigh’s Disease
3. rr - Affected by Leigh’s Disease

X linked Genotypes can be...

1. XX - Unaffected Female
2. X’X - Carrier Female
3. X’X’ - Affected Female
4. XY - Unaffected Male
5. X’Y - Affected Male

Statistics in Populations

Leigh’s Disease is a type of Mitochondrial Disease. Every 1 out of 6,000 people have a Mitochondrial Disease.  The incidents of Leigh’s Disease is uncertain.

Children and Leigh's Disease

Leigh’s Disease is most often passed to a child through autosomal recessive transmission.  This means the disease is not dominate, therefore you need both parents to be a carrier, or to be affected, for a child to get it.  If both parents are carriers, Rr, then they have a 25% chance of having an unaffected child, a 25% chance of having an affected child, and a 50% chance of having a carrier child. Use the diagram below as a visual aid to better understand what I just explained.

If both parents are unaffected by Leigh’s Disease, RR, there is a 100% chance that their children will also be unaffected.   If one parent is affected, rr, and one parent is a carrier, Rr, there is a 50% chance that their child will be affected by Leigh’s Disease, and a 50% chance it will be a carrier.

Diagnosis

Leigh’s Disease is hard to diagnose because of the wide range of symptoms that may, or may not, occur.  A genetic test for a specific mitochondrial DNA mutation is often very helpful.  A muscle biopsy can also be used to figure out if a person has an abnormality in their mitochondria.  There is not one exact way to diagnose Leigh’s Disease. 

Symptoms of Leigh's Disease

Physical symptoms of Leigh’s Disease include loss of inquired motor skills, loss of appetite, vomiting, and seizures.  Symptoms usually occur during the first year of a person’s life.  They can include loss of balance and coordination, and vomiting. Cells that are affected with Leigh’s disease do not produce as much ATPs which may lead to irreversible damage to cells that require more energy, like brain cells. The main reason babies get brought to a doctor is because they are not developing skills like babies that are not affected with Leigh’s disease.

Life Expectancy

The life expectancy for patients with Leigh’s Disease is a year after symptoms start.  Children usually develop this genetic disease from months after birth to 2 years of age.  The outlook for someone who suffers from Leigh’s Disease is not good.  They tend to only live anywhere from a few years after diagnosed, to their young teenage years.  However, there have been rare cases of adults developing Leigh-like disease.  These adults often live longer than when a child develops the disease. 

Treatments

There is no cure for Leigh’s Disease.  Treatments can include Thiamine or Vitamin B1.  Physical therapy also helps with muscle strength and with range of motion.

For people with X linked Leigh’s Disease, a low carbohydrate, high fat diet is recommended.

Everyday Life with Leigh's Disease

Life for a baby with Leigh’s Disease includes many doctors visits and tests.  Babies often have trouble breathing and developing motor skills. Parents of a baby with this disease are stressed and frantic searching for reasons why their baby is constantly sick.  Life for a baby with Leigh’s Disease is usually short, but the impact on their family is forever.

Limitations

Any limitations? Certainly.  Children with Leigh’s Disease have trouble learning at the same pace as children who don’t have the disease.  Affected children lose motor skills and usually have heart problems.

Organizations for Support

These are some sites that may help a family that suffers from Leigh's Disease

United Mitochondrial Disease Foundation (UMDF)

8085 Saltsburg Road
Suite 201
Pittsburgh, PA 15239
United States
Tel: (412)793-8077
Fax: (412)793-6477
Tel: (888)317-8633
Email: info@umdf.org
Internet: http://www.umdf.org

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223
Email: http://rarediseases.info.nih.gov/GARD/EmailForm.aspx
Internet: http://rarediseases.info.nih.gov/GARD

Will a Cure be found?

There is no cure for Leigh's Disease.   Research is going into finding a cure for Mitochondrial Diseases though.

Sources

"Genetic Counseling." Ornl.gov. Ed. Meghan E. Carey. U.S. Department of Energy Genome Programs, 29 Sept. 2008. Web. 10 Mar. 2011. <http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genecounseling.shtml#>.

"Leigh's Disease." Cigna.com. National Organization for Rare Disorders, Inc.® (NORD), 11 Mar. 2009. Web. 10 Mar. 2011. <http://www.cigna.com/healthinfo/nord392.html>

Autosomal recessive transmission example. Digital image. Psychology.wikia.com. Web. 11 Mar. 2011. <http://psychology.wikia.com/wiki/Recessive_gene>.

Weiss, Thomas C. Disabled-world.com. 16 Feb. 2010. Web. 11 Mar. 2011. <http://www.disabled-world.com/disability/types/leighs-disease.php>.

Bainbridge, Laura. "Leigh's Disease." Introduction. Understanding and Coping with Mitochondrial Disease, A Guide for Patients and Parents. Tuckerstime.com. Web. 11 Mar. 2011. <http://www.tuckerstime.com/leigh's_disease.htm>.