Diagnosis Delays of Up to Three Years Still Common in Mucopolysaccharidosis, Study Finds

It still takes doctors in Holland up to three years to diagnose the rare disease mucopolysaccharidosis — a situation that hasn’t changed in three decades, researchers report.

They called for new national guidelines that could help doctors do a better job of screening children with developmental problems for mucopolysaccharidosis and other rare disorders.

The team’s study, “Failure to shorten the diagnostic delay in two ultra-orphan diseases (mucopolysaccharidosis types I and III): potential causes and implications,” appeared in the Orphanet Journal of Rare Diseases.

A delay in diagnosis is a problem that many people with a rare disease experience. These delays often lead to the disease worsening — because doctors are unable to prescribe treatments for a disorder they haven’t been able to identify. An early diagnosis means patients can begin treatments quicker.

Because 80 percent of rare diseases are inherited, an early diagnosis also allows patients to obtain genetic counseling about their condition. This can help them make informed decisions about topics such as whether to have children.

Dutch researchers wanted to know if the medical profession had been able to reduce the time it takes to diagnose mucopolysaccharidosis types I and III in the past several decades. Type III is also known as Sanfilippo syndrome.

The study that the team conducted at the Academic Medical Center in Amsterdam was based on interviews with patients whom doctors had diagnosed with either type I or III of the disease between 1988 and 2017. In the case of young children, researchers interviewed parents.

The team used the answers to calculate the time between patients’ first visit to a doctor for their symptoms and their  diagnosis.

Twenty-nine patients had the type I disease. There are two categories of type I severity. It took patients with the most severe form, called Hurler, a median of eight months to obtain a diagnosis. It took those with the least severe form more than three times as long — a median of 28 months.

The delay was even longer for the 46 patients with the type III disease — 33 months, or almost three years.

“The time to diagnosis in patients with MPS [mucopolysaccharidosis] I and MPS III has not changed between 1988 and 2017 in the Netherlands,” the researchers wrote. “A long delay between the first visit to a medical doctor for symptoms related to the disease and the final diagnosis is common.”

The findings suggest that the current approach to improving the diagnosis of mucopolysaccharidosis — increasing awareness of it — has failed, the team said.

They called for new national guidelines on screening children with developmental delays for rare diseases.