Greenville Hosts the 2008 22q13 Deletion Foundation Conference

You may have seen the WYFF News at 6:00 coverage highlighting this international conference in Greenville. This was the sixth biennial gathering of families from around the world, meeting for support, education, and genetic evaluations for their children who have a rare genetic disorder called 22q13 deletion syndrome or Phelan-McDermid syndrome.

In this condition there is a small piece missing from one of the chromosomes 22. This deletion is detected through chromosome analysis and confirmed through a more precise chromosome test called FISH.

Humans normally have a total number of 46 chromosomes or 23 pairs, with one member of each pair coming from each parent. Chromosome 22 is one of the smallest chromosomes and was the first chromosome to be fully sequenced in the Human Genome Project. It is estimated that chromosome 22 contains 500-800 genes.

Physical features of Phelan-McDermid include poor muscle tone in the newborn period, severe developmental delays, absent or significant speech delay, long eye lashes, and large, fleshy hands. Many of the behavioral findings are similar to those in autism spectrum disorders including repetitive or stereotypical movements and decreased social interactions. The incidence of the condition is not known due to lack of clinical recognition and consequently under-diagnosis. In most families, the deletion has occurred only in one family member.

Patients with this syndrome are advised to receive routine examinations by their family physician. Early intervention therapies proving beneficial are physical therapy, communication therapies, exercise and sports activities, and music therapy. Disabilities are lifelong with individuals requiring supervision and care.

For more information on 22q13 deletion syndrome or Phelan-McDermid syndrome, visit the Foundation's website at www.22q13.org/home.html. Dr. Katy C. Phelan, who first identified this genetic condition, is the former director of the clinical cytogenetics laboratory at the Greenwood Genetic Center.

Learning More About Type 1 Diabetes

Type 1 diabetes or insulin dependent diabetes mellitus (IDDM) is a chronic condition characterized by low levels or no production of insulin. Insulin is a hormone produced by the pancreas and insulin's job is to transport sugar or glucose into the body's cells. Glucose is the primary source of energy for the cells. In type 1 diabetes an individual's immune system attacks and destroys its own insulin producing cells resulting in little or no insulin levels and subsequent increases in blood glucose levels. Type 1 diabetes can develop at any age but many cases appear in childhood or late adolescence.

The exact cause of type 1 diabetes is unknown but possible causative factors include immune problems, exposures to certain viruses, and genetics. It is known that having a parent or sibling with type 1 diabetes increases an individual's risk of also developing the disease. The genetics of type 1 diabetes is complex with research suggesting at least 20 different gene regions associated with the condition. A current research program at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is focusing on identifying specific genes that may predispose one to developing the disease and how these genes operate.

A recent publication from the Centers for Disease Control (CDC) revealed some dramatic estimates on the incidence, prevalence, complications, and costs of diabetes.  This study indicated that 6.3% or 18.2 million people in the United States have type 1 diabetes.  Prevalence rates in people aged 20 and older, grouped by ethnicity revealed that non-Hispanic whites had a prevalence rate of 8.4%, non-Hispanic blacks at 11.4%, Hispanic-Latino Americans at 8.2%, and American Indians/Native Alaskans have a prevalence of 14.9%.  In 2000, diabetes was the 6th leading cause of death in the country. Additional health complications of diabetes are extensive and include heart disease, stroke, high blood pressure, blindness, and kidney disease.  The estimated medical costs and costs due to disability / work loss totaled $132 million per year.

While research is on-going, type 1 diabetes has no cure; however, significant improvements have been made in disease management and treatments. With diligent care, individuals are living longer, healthier lives.

The Greenwood Genetic Center's annual Summer Genetics Lecture Series in June will focus on Type 1 diabetes, emphasizing current research, clinical trials, and possible future means of prevention. Sandra Weber, MD, endocrinologist from Greenville Memorial Hospital, will speak on "Natural History of Type 1 Diabetes Mellitus". This talk is open to the public at no charge and we invite you to attend. Please look for additional information in the newspaper or call the GGC for date, time, and location.

Genetic Legislation: GINA

Today there are more than twenty companies that offer "personalized genomics" tests directly to consumers. These tests are designed for a number of uses including confirming paternity, predicting one's risk to develop certain diseases, determining personality profiles, and determining one's propensity to develop specific addictions.

There are companies like ScientificMatch.com which will assist you in finding a DNA compatible mate at a cost of $995; their claim is that people are more attracted to those with very different or opposite immune systems. There are companies that claim they can identify an individual's specific nutritional needs and develop a dietary program, offering to sell the needed dietary supplements at a greatly inflated price compared to purchase over the counter.

Published in this month's issue of the American Journal of Human Genetics is the statement that there is insufficient scientific evidence that genomic profiles are useful in measuring risk for common diseases or in developing personalized diet for disease prevention.

Specific factors compound the concerns or dangers of direct to consumer (DTC) genetic testing. The Food and Drug Administration does not regulate most of these tests nor is there a proficiency standard required of these companies. Technology is changing daily, allowing the costs for these tests to drop significantly. At one time it cost several million dollars to have your entire genome analyzed; last year the cost dropped to about one million dollars and today a Massachusetts company will do it for $350,000. It is expected that cost will continue to drop.

A former director of the National Institutes of Health defined genetics as the "science of differences and can be used to categorize people or stigmatize them or subject them to social or economic discrimination", offering the 20th century eugenics movement as an example. The director of the National Human Genome Research Institute and leader of the public arm of the Human Genome Project, Francis Collins, shares concerns about employers using genetic information in hiring, firing, or promotion decisions on the basis of someone possibly developing a disease in the future. There are some in the life insurance field who argue that those with better genes should not have to pay the same premiums as someone with a profile showing susceptibility to disease.

A legislative bill, GINA for Genetic Information Nondiscrimination Act, has near unanimous support in the US House and Senate but is being held in committee by one opposing senator from Oklahoma. This bill would provide the protection needed from discriminatory actions based on genetic information. The future of personalized medicine and treatment requires passage of protective legislation before these concerns become realities. This should be a topic of political discourse in this year's elections.

Mitochondrial DNA and Professional Baseball

Patient description: twenty-six years old, a professional athlete making an annual salary of more than $2 million dollars. This is not the typical description of someone suspected of having a mitochondrial disorder but this may indeed be the case for Rocco Baldelli. Baldelli plays center field for the Tampa Bay Rays and has been on the disabled list since March of this year; reason given is "mitochondrial disorder."

Mitochondria are organelles or structures within our cells whose function is to produce energy. The mitochondria convert the energy from food into a form that the cells can use, called ATP. ATP is the energy source for muscles and to continue exercising or playing, muscles must continually produce ATP. The more strenuous the exercise, the greater are the demands on the muscle.

Mitochondria are unique cell structures in that they contain their own DNA. Changes or mutations in mitochondrial DNA can occur as inherited changes or may occur by chance. Disorders resulting from mitochondrial mutations often involve multiple organ systems but are most pronounced in organs and tissues with high energy demands. Examples of these organs and tissues include the heart, brain, and muscles. Mitochondrial DNA, if damaged, has little ability to repair itself. Therefore, these changes can accumulate over time and symptoms may take years to surface.

In the case of Rocco Baldelli, he noticed changes in his endurance and strength within the last two years. Basic baseball activities like running, batting, and throwing left him extremely fatigued and weakened after short workouts. These conditions can be frustrating because it is often very difficult to specifically identify an exact reason or cause and assign the symptoms a specific name. Baldelli will remain on the disabled list "indefinitely until we find out something else that could possibly improve my situation."

For more information on mitochondrial disorders you may visit the following websites:

 

    • http://www.ghr.nlm.nih.gov
    • http://www.clevelandclinic.org/health/health-info/docs/1600/1678.asp?index=6957

 

The Importance of Family History

Probably, we have all seen the well-designed commercials touting the important role of family history in healthcare. The commercials begin by asking, "Where does cholesterol come from?" and in response we see images of fried chicken, French fries, and red meat floating on the television screen. The commercial then adds that cholesterol can also come from "Aunt Helen" or "Uncle George" illustrating that family inheritance can also contribute to elevated cholesterol levels.

The message in these commercials is significant. We know that family history is important to health; we understand that certain disorders can run in families. A recent survey indicated that 96% of Americans believe knowing their family history is important yet only about one-third of Americans have tried to write their histories.

My Family Health Portrait is a web tool developed by the Surgeon General's office to assist members of the public in detailing their family history. On this site one may record as much health information as is known and print for sharing with other family members and with their physicians.

Sharing family history with you doctor has several advantages in both pediatric and adult settings. Family history can be used for diagnosing and identifying risk for certain disorders; it can provide guidance on screening and other preventive efforts; it provides an educational opportunity to correct any misconceptions, and it serves to establish a rapport with the health provider.

The family history initiative is not limited to the lay population but also targets and encourages clinicians to collect detailed family histories (3 generations if possible). Identified barriers to physician use include lack of sufficient office time, lack of training in interpreting the history, lack of reimbursement for the service, and being provided inaccurate or incomplete family history information.

Family history collection tools have been developed for the healthcare professional's use and may be found at several web sites including the National Coalition for Health Professional Education in Genetics (NCHPEG) and the March of Dimes. To be used successfully, family history tools should not be too time consuming and should be easy to implement in the office setting. Increased public interest in family history can also be a motivating factor to healthcare providers to include into practice.

For more information or to view and complete a family history tool, you may visit the following sites:

 

  • NCHPEG - www.nchpeg.org
  • Family Health Portrait - www.surgeongeneral.gov/familyhistory/
  • March of Dimes - www.marchofdimes.com
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