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.