Table 4.

Laboratory Technical Considerations for Genes Causing Nonketotic Hyperglycinemia

Gene 1Special Considerations
AMT None
GCSH To date only 2 persons w/biallelic GCSH variants have been identified; however, the pathogenicity of the variants has not been established.
GLDC
  • GLDC analysis is complicated by the presence of a processed full-length pseudogene w/97.5% homology to the true gene, differing in single-nucleotide variants along its length [Takayanagi et al 2000]. Primers based on intronic sequence are required to avoid amplification of the pseudogene.
  • 20% of pathogenic GLDC variants are large deletions that have occurred on various haplotypes & in different ethnic groups as a result of nonallelic homologous recombination of Alu repeats.
1.

Genes are listed alphabetically.

From: Nonketotic Hyperglycinemia

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