Neonatal adrenoleukodystrophy (NALD) is the former name of a rare genetic disorder known as Zellweger spectrum disorder (ZSD). Doctors usually diagnose it shortly after birth, and treatment includes supportive care.

NALD refers to a moderate form of what used to be called ZSD.

It’s a rare genetic disorder that results from mutations in the peroxisomal genes. It causes peroxisomes that do not work properly, that are absent, or that are reduced in quantity.

Peroxisomes help cells function, support brain development, and help form myelin, which is the protective coating that surrounds nerves.

Continue reading to learn more about NALD and ZSD, including the symptoms, cause, treatments, and outlook.

Although ZSD was historically described as four separate disorders, one of which was NALD, it’s now understood as one disorder that exists on a continuum.

The names for the disorders in the spectrum, ordered from most to least severe, are:

ZSD causes symptoms that affect multiple organs. Many of these symptoms are present at birth and worsen over time.

Symptoms can include:

Not everyone with ZSD experiences the same symptoms. More severe ZSD causes more severe symptoms.

A 2020 survey of parents with children who have ZSD suggests that symptoms can vary. Some children did not experience symptoms like seizures or hearing loss. Verbal communication and mobility symptoms also occurred on a spectrum.

ZSD is a rare genetic disorder that results from multiple mutations in the peroxisomal genes. It’s autosomal recessive, which means a person acquires the disorder by getting one copy of the mutated gene from each parent.

The mutation causes either a lack of or a reduction in functional peroxisomes in cells. Peroxisomes usually help cells function, support brain development, and help form myelin, which is the protective coating that surrounds nerves. They also help break down very-long-chain fatty acids.

ZSD can affect all body systems because peroxisomes are present in all cells.

Doctors typically diagnose ZSD shortly after birth.

If they suspect ZSD, they’ll order a variety of tests to confirm the diagnosis and better understand its severity.

Tests can include:

There’s no cure for ZSD.

Treatment involves supportive care to reduce the effect of the symptoms. This can include:

The outlook with ZSD can depend on the severity, though many people with a diagnosis of moderate to severe ZSD live under 2 years.

The results of a 2022 review of research suggest that ZSD severity affects a child’s outlook. The researchers found that 83% of those with severe ZSD died by the time they reached 2 years, compared with 24% for those with moderate ZSD.

Those with mild ZSD all survived at least 2 years.

What’s the life expectancy with neonatal adrenoleukodystrophy?

Older research suggests that the life expectancy with NALD is 3 years. However, 77% of those with a diagnosis who live at least 1 year and don’t have progressive disease reach school age.

NALD is a moderate form of what used to be called ZSD, a peroxisome biogenesis disorder. It results in a lack of peroxisomes, fewer peroxisomes, or peroxisomes that don’t work as they should.

It’s a genetic disorder caused by mutations in certain genes.

Symptoms usually affect all body systems because peroxisomes are present in all the body’s cells.

Treatment typically involves supportive care to reduce the effect of the symptoms.