FamilyInfo: *Family 2, Hispanic

FamilyHPOs: HP:0001987, HP:0500149, HP:0003572

FamilyNotHPOs: HP:0003218

FamilyGenotypingMethod: All seven exons including intron/exon boundaries of the NAGS gene were amplified and sequenced.

Variant: NM_153006.2(NAGS):c.1025delG (p.Arg342Profs)

ClinVarID: 2427

gnomAD: Absent

Proband: Family 2-Patient 1

Case#: Patient 1, male, died on DOL 4, from the Faroe islands

CaseHPOs: HP:0003811 (neonatal death)

CaseHPOsFreeText: At 16 hours old, began grunting, was jittery, and had tachypnea. At 48 hours, had increased jitteriness, hypertonia, hypothermia, and alkalosis. Coma and death at 4 days. In urine, undetectable citrulline, argininosuccinate, and orotic acid. Plasma amino acids showed extremely elevated glutamine and alanine suggestive of hyperammonemia. No ammonia levels were available.

CaseNotHPOs: HP:0003218 (Orotic aciduria)

CasePreviousTesting: Analysis of urea cycle enzymes on post mortem liver tissue: CPSI activity was 30.7 U (normal >12), basal NAGS activity was 10 U (normal >34), arginine stimulated NAGS activity was 20 U (normal >144).

CaseMethod1: PCR

CaseMethod2: Sequencing

CaseGenotypingMethod: Tissue or DNA from the deceased infant of family 1 was unavailable; blood genomic DNA from both parents to search for a mutation in the NAGS gene. All seven exons including intron/exon boundaries of the NAGS gene were amplified and sequenced.

Variant: NM_153006.2(NAGS):c.971G>A (p.Trp324Ter) (homozygous) (based on parental results; both parents are heterozygous)

ClinVar: 2428

gnomAD: Absent

VariantEvidence: NA

PMID: 27037498

Gene: NAGS

MonDO: MONDO:0009377

InheritancePattern: AR