Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Norrie Disease

Less commonly called Anderson-Warburg syndrome.

What is Norrie Disease?

• Norrie disease is a genetic disorder that affects the eyes
• The disease leads to blindness in male infants shortly after being born
• Norrie disease results in abnormal development of the retina
• This is a very rare disorder with less than 1,000 recorded cases
  • Overall, the true prevalence of Norrie disease remains unknown

How Do You Get It?

• Norrie disease is caused by mutations in the NDP gene, which is found on the X chromosome
  • This gene codes for a protein called norrin, which plays a role in the development of various cells and tissues
  • More specifically, the protein is linked to retinal development
• Since the illness is inherited in an X-linked recessive pattern, Norrie disease almost exclusively impacts males
  • Only a very limited number of cases affecting females have been reported
• Cases have been reported from around the world and Norrie disease doesn’t appear to be linked to certain ethnic groups

What Are the Symptoms?

• Symptoms of Norrie disease include:
  • Total vision loss shortly after birth
  • Cataracts
  • Wasting of the iris
  • Leukocoria, in which the pupils turn white when light is shone on them
  • Developmental delays
  • Mild to moderate severe intellectual disability
  • Psychosis
  • Hearing loss, typically occurring later in life

How Is It Treated?

• There is no cure for Norrie disease and management of the disease is mostly symptomatic and supportive
• Regular monitoring from hearing and vision specialists is recommended for patients, even after vision has deteriorated
• Dual sensory clinics have been suggested as useful for patients with Norrie disease, along with other conditions that can lead to blindness and deafness
• The psychological burden of Norrie disease is heavy due to dual blindness and deafness, leading to severe isolation in some cases. Emotional and mental health support can be essential for patients, particularly on the onset of hearing loss

Where Can I Learn More???

• Learn more about this disease from the Norrie Disease Foundation.