PEX1 (p.G843D, c.2097_2098insT, c.2916delA) were once thought to be distinct disorders but are now considered to be part of the same disease spectrum. Individuals with Zellweger syndrome develop symptoms during the newborn period including weak muscle tone, feeding problems, hearing loss, vision loss, and seizures and may also develop life-threatening problems in other organs and tissues, such as the liver, heart, and kidneys. Children with Zellweger syndrome typically do not survive beyond the first year of life. People with NALD or infantile Refsum disease have more variable features and usually do not develop signs and symptoms of the disease until late infancy or early childhood.