Variant 1: NM_000257.4(MYH7):c.2167C>G (p.Arg723Gly)

ClinVar: 42885, https://www.ncbi.nlm.nih.gov/clinvar/variation/42885/

gnomAD: n/a

Variant 2: NM_000257.4:c.599C>T (p.Ala200Val)

CAID: CA389052449, http://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_caid?caid=CA389052449

gnomAD: n/a

NM_000152.4(GAA):c.-32-13T>G

Variant: NM_013391.3:c.326A>G (p.His109Arg)

VariantEvidence: The above variant was expressed in E coli through an expression vector and DMGDH activity was measured and purified for both the mutant and the wild-type. The flavination in the mutant protein showed a 2-fold decrease compared to the wild-type and the under-flavinated mutant revealed a 27-fold decrease in enzyme activity compared to the flavinated wild-type. Experiments with trypsin digestion also confirmed that the under-flavinated variants may be less stable than the wild-type enzyme.

Variant1: NM_001902.5:c.200C>T (p.Thr67Ile)

Variant2: NM_001902.5(CTH):c.718C>G (p.Gln240Glu)

VariantEvidence: Mutant proteins were expressed in the Escherichia coli by site-directed mutagenesis, with the codon change confirmed by DNA sequencing. Recombinant CTH was expressed and the proteins were purified and the levels detected. The activity of the T67I mutant was 0.6 μmol min−1 mg−1 protein, 3.5-fold lower than the wild-type, with H2S generation from homocysteine and cysteine showing similar decreases of 4-fold and 2-fold respectively. The Q240E mutant was significantly lower, with only 0.03 μmol min−1 mg−1 protein and no detectable H2S generation. See Purification and Kinetic Properties of the Patient Mutations T67I and Q240E for details.

Furthermore, the variant was tested for PLP responsiveness. While the wild-type alleles exhibited ~80% content, the T67I and Q240E variants only displayed 19% and 0.3-1% saturation respectively. See Figure 3 for details.

Variant1: NM_001902.5:c.200C>T (p.Thr67Ile)

Variant2: NM_001902.5(CTH):c.718C>G (p.Gln240Glu)

VariantEvidence: Mutant proteins were expressed in the Escherichia coli by site-directed mutagenesis, with the codon change confirmed by DNA sequencing. Recombinant CTH was expressed and the proteins were purified and the levels detected. The activity of the T67I mutant was 0.6 μmol min−1 mg−1 protein, 3.5-fold lower than the wild-type, with H2S generation from homocysteine and cysteine showing similar decreases of 4-fold and 2-fold respectively. The Q240E mutant was significantly lower, with only 0.03 μmol min−1 mg−1 protein and no detectable H2S generation. See Purification and Kinetic Properties of the Patient Mutations T67I and Q240E for details.

Furthermore, the variant was tested for PLP responsiveness. While the wild-type alleles exhibited ~80% content, the T67I and Q240E variants only displayed 19% and 0.3-1% saturation respectively. See Figure 3 for details.

Families 1 and 2

Variant, NKX6-2: c.121A>T; p.Lys41∗ (NM_177400.2), results in stop codon at amino acid 41 resulting in mRNA decay which causes the loss of the functional homeobox.

Families 1 and 2

Variant, NKX6-2: c.121A>T; p.Lys41∗ (NM_177400.2), results in stop codon at amino acid 41 resulting in mRNA decay which causes the loss of the functional homeobox.