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 rare disease that we will be learning about today is:

Galactosemia

What is Galactosemia?

• Galactosemia is a rare, genetic, metabolic disorder that impacts the ability to metabolize the sugar galactose
  • As a result, galactose-related substances build up in the organs, causing signs and symptoms
• In European people, the incidence rate is about 1 in 60,000, but in other populations, the frequency varies
• The disorder was first described in 1917 by Friedrich Goppert, a physician from Germany
• People with the disease either have very low or none of the enzymes necessary to process galactose
  • Galactose is a sugar found in milk, including human breast milk, and is normally converted into glucose
• Without intervention early in life, this disease can result in life-threatening problems
• There are three forms of galactosemia that have been identified:
  • Classic galactosemia
  • Clinical variant galactosemia
  • Duarte (biochemical) variant galactosemia

How Do You Get It?

• This is an autosomal recessive disease, meaning that both parents must pass along the mutation
• Galactosemia is the result of mutations impacting the GALT gene
• Risk appears to be the same for males and females
  • People of Irish ancestry are more likely to have galactosemia
  • Clinical variant galactosemia appears to occur more often in people of African ancestry, particularly from South Africa

What Are The Symptoms?

• Within a few weeks after birth, the first symptoms of galactosemia begin to appear; the first signs are loss of appetite and excessive vomiting
• Other symptoms can include:
  • Hypotonia
  • Lethargy
  • Hepatocellular damage
  • Diarrhea
  • Jaundice
  • Proteinuria
  • Abdominal swelling
  • Weight loss
  • Infections
• Without early treatment, symptoms will continue to progress, such as:
  • Cataracts
  • Impaired mental and physical development
    • This can result in speech and behavioral difficulties
  • Ovarian impairment
  • Brain damage
  • Liver failure
  • Kidney dysfunction
• In the Duarte variant, signs and symptoms may not be present, though language develop might still be affected

How Is It Treated?

• Prompt treatment through the elimination of lactose and galactose from the diet is critical and can help patients avoid the most severe symptoms and complications of galactosemia
  • This effectively means a diet that is free of most dairy products
• While this method is vital for preventing the most acute complications, it doesn’t stop more long term problems impacting the ovaries and brain
  • Long term issues such as speech problems, ovarian failure, learning problems, and neurological dysfunction may still appear
• Speech therapy, behavioral therapies, and additional learning/educational support may be required for many patients.
• There is a need for more disease-modifying therapies/cures for galactosemia

Where Can I Learn More???

• Learn more about this disease from the Galactosemia Foundation.
• Check out our cornerstone on this disease here.