Zellweger spectrum disorders

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Zellweger spectrum disorders are a group of rare genetic conditions that affect how the body processes certain fats. The disorders in this group include Zellweger syndrome, neonatal adrenoleukodystrophy (NALD), infantile Refsum disease, and hyperpipecolic acidemia. They are also called peroxisomal biogenesis disorders or ZSS.

Cause and genetics:
These disorders are inherited in an autosomal recessive way, meaning a child usually develops symptoms only if both parents carry the faulty genes. Mutations in at least 13 PEX genes, which make peroxins needed for peroxisomes, disrupt how these cell parts work. Peroxisomes help break down fats and other substances, so when they don’t work right, problems can arise. If one parent carries the gene and the other does not, the child is typically a healthy carrier.

Who is affected:
Both boys and girls are equally affected.

Symptoms:
Symptoms vary but often appear at birth. Babies may have slow growth and low muscle tone, and there can be neurological problems such as seizures and delays in thinking and movement. Facial features commonly seen include a small chin, upturned nostrils, and a high-arched palate. Eye problems like cataracts and retinal issues can lead to vision loss, and hearing loss can occur in early life. Other issues may include an enlarged liver or spleen, heart defects, and breathing problems due to weak muscles.

Diagnosis:
Diagnosis involves tests that check how well peroxisomes are working and genetic testing to find PEX mutations.

Treatment and prognosis:
There is no cure, but a team of specialists (such as neurologists, endocrinologists, and pediatricians) can help manage symptoms. Early intervention with special education, physical therapy, and other therapies can help. Ongoing research and clinical trials aim to better understand the disorders. Many babies with the most severe form do not survive infancy, while milder forms can allow longer survival. The condition occurs in about 1 in 50,000 people.