Over the course of several years, Dr. Tropez-Sims conducted every test imaginable on Darian, but still there was no answer that explained his condition.
It wasn’t until she referred him to the National Institutes of Health (NIH) Undiagnosed Diseases Program (UDP) that questions were answered.
The program is for patients with longstanding medical conditions that elude diagnosis by the referring physician. It is designed to provide answers to patients with mysterious conditions while advancing medical knowledge of rare and common diseases.
The NIH began testing Darian in 2012. Welch called consistently for updates, but years passed before she had her answer.
In 2015, Darian was diagnosed with Niemann Pick Disease Type C; a disease that he’d previously tested negatively for, but now because of a new testing method used by the NIH, a successful diagnosis was possible.
“He’s not the first person to have it, but he’s the first person to find out through this test,” Welch said.
According to Dr. Tropez-Sims, Niemann Pick is a genetic mutation caused by a defect on the Niemann Pick gene. There are four types (A, B, C, and D); and the type determines the symptoms and what stage of life the disease will manifest.
Type A shows up early in life and people with Niemann Pick Type A typically have a cherry-red spot in one of their eyes. Type B shows up later in childhood or even as late as teenage years, and is characterized by problems with respiratory infections.
Both Type A and B can include swelling of the abdomen. Type C and D can occur as early as infancy or as late as adulthood. Patients like Darian who have Type C or D experience symptoms such as an enlarged spleen and liver, seizures, difficulty moving, learning problems, intellectual decline, loss of muscle tone, inability to walk, and slurred speech.
Darian is one of only about 500 people in the world who have Niemann Pick Disease Type C, according to the Addi & Cassi Fund. According to Dr. Tropez-Sims, both of Darian’s parents are carriers, but because the disease is so rare, children and parents are not tested for the mutation unless the child begins to show symptoms. Every person carries the Niemann Pick gene, but it will only cause the symptoms seen in Niemann Pick Disease if there is a mutation.