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Zellweger Syndrome Spectrum

The Zellweger Syndrome Spectrum is an overlap of 3 different recessive inherited genetic diseases. The first being Zellweger syndrome (the most severe), the second being neonatal Adrenoleukodystrophy (moderately severe) and infantile Refsum disease (the least severe). All of these diseaes are put under the Zellweger Syndrome spectrum because they each affect the assembly of specific peroxisomes inside cells. These mutations cause abnormalities in formation and function of the peroxisomes, small sacs that digest/process toxins and certain lipids within each cell.

If offspring shows homozygous dominance of a Zellweger syndrome disease, they acquired both genes with a mutation, G843D, in their peroxisome-creating gene, PEX1. These children would be unlikely to reproduce, but would pass on their dominant gene to their offspring, creating an affected individual or carrier individual (phenotype). Homozygous dominance would produce an affected offspring with distinct facial features, low muscle tone, seizures and seeing/hearing difficulties (genotype).

If offspring shows heterozygous dominance of a Zellweger syndrome disease, they acquired only one gene with a mutation, G843D in their peroxisome-creating gene, PEX1. These children would become carriers (phenotype). Heterozygous dominance would produce an affected offspring with distinct facial features, low muscle tone, seizures and seeing/hearing difficulties (genotype).

If offspring shows homozygous recessiveness of a Zellweger syndrome disease, they acquired no genes with mutations in their PEX1 gene. A Homozygous recessive offspring would be non-affected by the G843D mutation. These children would remain recessive homozygous, and not pass on any mutations to their offspring, making them non-affected or carrier.

Resources

"23andMe - Genetic Testing for Ancestry." Health and Traits - Zellweger Syndrome Spectrum. 23 and Me, n.d. Web. 15 Sept. 2014.