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Rare Childhood Diseases

There are often no available treatment options for rare childhood disorders. When new medications do become available, the price is often too high for families already struggling with the substantial cost of daily medical care. Stem cell and gene therapies, alone or combined, are emerging as one-time therapies to halt or prevent the progression of some of these disorders.

Between 6,500 and 8,000 rare and/or genetic diseases have been identified worldwide. 80% of rare diseases are genetic and present throughout a person’s life, even if symptoms do not immediately appear. Children are often diagnosed at birth through newborn screening – or later in childhood and early adulthood when symptoms emerge. Some of these diseases may have devastating or life-threatening consequences. Others may require the need for life-long medical treatment and chronic care or lifestyle changes with vigilant monitoring. All are life altering.

30% of children with rare disease will not live to see their 5th birthday; rare diseases are responsible for 35% of deaths in the first year of life. The majority of rare diseases are thought to be genetic. In some cases, genetic changes that cause disease are passed from one generation to the next. In other cases, they occur randomly in a person who is the first in a family to be diagnosed. The exact cause of many rare diseases is still unknown.

All our traits – height, eye color, foot size – are determined by the genes that we inherit from our parents. A gene is a working subunit of DNA, which resides in the core of every cell in your body and carries a complete set of instructions for making everything the cell will ever need. DNA is like a huge database, made up of millions of chemical building blocks. The DNA in each human cell contains about 100,000 genes, each of which is responsible for making one specific thing, such as an enzyme. When genes are working properly, our bodies develop correctly and work well. But small changes, or mutations, in just one gene can have huge effects, sometimes leading to birth defects or disease.


In the United States, a rare disease is defined as one that affects fewer than 200,000 people. An estimated 30 million people in the United States are living with rare diseases – 10% of the U.S. population. Global Genes estimates that more than 350 million people worldwide are living with rare disorders. This estimate has been used by the rare disease community for several decades to highlight that while individual diseases may be rare, the total number of people with a rare disease is large. If all the people with rare diseases lived in one country, it would be the world’s 3rd most populous country.

Federal Research

Rare diseases became known as orphan diseases because drug companies had no incentive to develop treatments when the number of people affected by a single rare disease was so small. The FDA passed the Orphan Drug Act in 1983 to create financial incentives that would encourage companies to develop new drugs for rare diseases. During the first 25 years of the Orphan Drug Act, approximately 400 new drugs have been approved by the FDA and brought to market for all rare disease patients combined. According to the Kakkis EveryLife Foundation, 95% of rare diseases have no FDA-approved drug treatment. Approximately 50% of rare diseases do not have a disease specific foundation supporting or researching their rare disease. The National Institutes of Health (NIH) also works to support rare disease research through several NIH Institutes and Centers.

The National Center for Advancing Translational Sciences (NCATS) focuses on getting new cures and treatments to patients more quickly and coordinates the NCATS Office of Rare Diseases Research (ORDR).

Advances in Cell and Gene Therapies

We are currently undergoing a technological revolution in medicine and the range of possible gene and cell therapies for rare diseases is growing at an extremely rapid rate. Advanced therapy medicinal products (ATMPs) are currently the hottest topic in novel medicines, particularly for inherited diseases. Pediatric patients in particular may benefit enormously from these novel therapies. It now seems likely that there will be gene or cell therapies developed for a large number of inherited diseases – there are several currently in various stages of development.

Our greater understanding of the human genome has led to a rapid understanding of the genetic basis of many inherited diseases. Remarkable technological advances have enabled specific engineering of adult human stem cell populations and led to new therapeutic options for a wide range of inherited and acquired conditions, challenging our conventional view of “medicines.” At present, both cell and gene modified cell therapies are almost exclusively being developed and tested in clinical trials at large academic research centers. Clinical trials are also sometimes available through compassionate use exception participation in protocols being tested for other conditions. The coordination of clinicians, scientists and patient partnerships between universities and hospitals is critical in rare disease clinical trials.

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  • PMC – Gene and Cell Therapy for Children: New Medicines, New Challenges
  • Clinical
  • Global Genes
  • NORD
  • United Leukodystrophy Foundation
  • National MPS Society
  • United Mitochondrial Disease Foundation
  • Children Living with Inherited Metabolic Disease (CLIMB)
  • EveryLife Foundation
  • National Institute of Neurological Disorders and Stroke
  • Rare Diseases Clinical Research Network (RDCRN)
  • Therapeutics for Rare and Neglected Diseases (TRND)
  • Global Rare Diseases Patient Registry Data Repository (GRDR)
  • Genetic and Rare Diseases Information Center (GARD)