NHGRI scientific director Daniel Kastner, M.D., Ph.D., a pioneer in the field of autoinflammatory diseases, and his team discovered CRIA, which has symptoms including fevers, swollen lymph nodes, severe abdominal pain, gastrointestinal problems, headaches and, in some cases, abnormally enlarged spleen and liver.
The disorder has characteristics typical of an autoinflammatory disease, where the immune system appears to be activated without any apparent trigger. Although the condition is not life-threatening, patients have persistent fever and swollen lymph nodes from childhood to old age, as well as other symptoms that can lead to lifelong pain and disability.
When confronted by patients’ symptoms, who were first seen at the NIH Clinical Center, researchers looked for infections and cancer as the cause. After those were ruled out, they sought answers in the genome, a person’s complete set of DNA. Kastner and his team sequenced gene regions across the genome and discovered only one gene – RIPK1 – to be consistently different in all patients.
Researchers identified a specific type of variation in the patients: a single DNA letter at a specific location incorrectly changed. This change can alter the amino acid added to the encoded protein. These are called “missense” mutations.
Remarkably, each of the three families had its own unique missense mutation affecting the very same DNA letter in the RIPK1 gene. Each affected person had one mutant and one normal copy of the gene, while the unaffected family members had two normal copies of the gene.
The researchers also looked at 554 people with sporadic unexplained fever, swollen glands and other symptoms or diseases, and then at over a quarter million people from public sequence databases to see if they encountered the same RIPK1 mutations. When they did not find such mutations elsewhere, it was clear that they were onto something new.
“It was as if lightning had struck three times in the same place,” said Kastner, who led the NHGRI team. “This discovery underscores the tremendous power of combining astute clinical observation, state-of-the-art DNA sequencing, and the sharing of sequence data in large publicly-accessible databases. We live in a very special time.”
It was as if lightning had struck three times in the same place. This discovery underscores the tremendous power of combining astute clinical observation, state-of-the-art DNA sequencing, and the sharing of sequence data in large publicly-accessible databases. We live in a very special time.