NEWS BLOG from UPMC and the University of Pittsburgh Schools of the Health Sciences

Rare Disease Day Promotes Awareness, Research, Hope

by Jennifer C. Yates 1 Comment

What do spinocerebellar ataxias, dystonia and porphyria have in common? They are among 7,000 rare diseases identified in the United States. About 80 percent of these diseases are genetic, and many affect children. 


Today marks Rare Disease Day, which was established in Europe in 2008 on Feb. 29. That date was chosen because it’s so rare – only happening once every four years. In the lack of a Leap Year, the day is commemorated on Feb. 28 and March 1.
Rare diseases in the U.S. are defined as any illness affecting less than 200,000 people, according to the National Organization for Rare Disorders.   Rare diseases can be a challenge to diagnose, and treatments and support are often limited for patients because so few people are affected. Rare diseases are often chronic, progressive, disabling and life threatening.
The National Institutes of Health’s Office of Rare Diseases Research was established to help raise awareness, bring together resources for patients and promote research into rare diseases.
Do you have a rare disease or know someone who does? Help raise awareness of the condition by sharing your story with us in the comments section below.

One Response to Rare Disease Day Promotes Awareness, Research, Hope

  1. Christin Leistner says:

    A very close friend of mine has a 1 year old daughter who was born with a rare disease called Urea Cycle Disorder. My friend has a deficiency called Ornithine Transcarbamylase Deficiency which is what caused her daughter to be born with UCD. Since today is National Rare Disease Day, and I would like to make more people aware of this matter, I have included some information below to enlighten you all on this rare disorder…

    Ornithine Transcarbamylase Deficiency(OTC):

    Ornithine transcarbamylase (OTC) is an enzyme of the urea cycle. The urea cycle functions primarily in the liver, and is a metabolic pathway that detoxifies ammonia by converting it into urea. Ammonia is generated from the conversion of proteins and nucleic acids in our diet as well as due to normal cellular turnover. Defects of the urea cycle result in hyperammonemia which can progress to brain edema and result in cognitive impairment or death.

    Ornithine transcarbamylase deficiency is an inborn error of metabolism usually caused by mutations in the OTC gene. Ornithine transcarbamylase deficiency affects approximately 1:16000 children, and accounts for nearly half of all inherited urea cycle disorders. Shown below is a schematic of a cell highlighting the various enzymes of the urea cycle.

    (for more information about this deficiency visit )

    Urea Cycle Disorder (UCD)
    A urea cycle disorder is a genetic disorder caused by a mutation that results in a deficiency of one of the six enzymes in the urea cycle. These enzymes are responsible for removing ammonia from the blood stream. The urea cycle involves a series of biochemical steps in which nitrogen, a waste product of protein metabolism, is removed from the blood and converted to a compound called urea in the blood. Normally, the urea is transferred into the urine and removed from the body. In urea cycle disorders, the nitrogen accumulates in the form of ammonia, a highly toxic substance, resulting in hyperammonemia (elevated blood ammonia). Ammonia then reaches the brain through the blood, where it can cause irreversible brain damage, coma and/or death.

    The onset and severity of urea cycle disorders is highly variable. This depends on the specific mutation involved and correlates with the amount of urea cycle enzyme function. Severe mutations result in zero to very little enzyme function and ability to detoxify ammonia, and cause severe urea cycle disorders. Mild to moderate mutations represent a broad spectrum of enzyme function, providing some ability to detoxify ammonia, and result in mild to moderate urea cycle disorders.

    (for more information about UCD visit: )

    Thank you for your time!

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