Every person has two copies of the NGLY1 gene. If one of those two copies is a mutation, a person will be a “carrier”. Being a carrier is not a problem as the one remaining normal copy of the NGLY1 gene is sufficient to produce enough N-glycanase. But if two carriers meet and have a child, they stand a 25% chance of producing a child with TWO mutated copies of the gene, hence a child that has the disease. 50% of their offspring will be carriers and the remaining 25% will be unaffected.
NGLY1 gene lies on Chromosome 3
Amongst the known patients, there is a variety of different mutations dispersed along the NGLY1 gene. The most common mutation seen in NGLY1 patients is the nonsense mutation p.R401X, or c. 1201A>T, where a change in one codon signals the cell to prematurely stop building the enzyme N-glycanase.
Detailed information provided by Genetics Home Reference:
- Cytogenetic Location: 3p24.2, which is the short (p) arm of chromosome 3 at position 24.2
- Molecular Location: base pairs 25,718,944 to 25,790,039 on chromosome 3 (Homo sapiens Annotation Release 108, GRCh38.p7) (NCBI)