Critical sample collection delayed? Urine organic acid analysis can still save the day! A new case of HMG-CoA synthase deficiency

© 2024 The Authors. Published by Elsevier Inc..

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase (mHS) deficiency is an autosomal recessive disorder of ketone body synthesis caused by biallelic pathogenic variants in HMGCS2. Clinical symptoms are precipitated by prolonged fasting and/or intercurrent illness with onset before the first year of life. Clinically, patients may present with hypo-/ non-ketotic hypoglycemia, metabolic acidosis, hyperammonemia, lethargy, hepatomegaly, and encephalopathy. During periods of decompensation, elevations of 4-hydroxy-6-methyl-2-pyrone (4-HMP), several hydroxylated hexanoic and hexenoic acid species, and medium-chain dicarboxylic acids in the absence of significant ketonuria may be observed in the urine organic acid profile. Abnormalities may also be observed in plasma which includes elevated acetylcarnitine (C2) and 3-hydroxybutyryl/3-hydroxyisobutyryl (C4-OH) carnitine. We report a patient who presented to the ED at 13 months of age with an undetectable point-of-care blood glucose level. Continuous infusion of dextrose-containing intravenous (IV) fluids were required to correct the hypoglycemia and routine chemistries were notable for an anion gap metabolic acidosis, transaminasemia, and elevated creatine kinase and lactate dehydrogenase. Urine and blood ketones were undetectable. Qualitative assessment of urine organic acids collected ∼46 and ∼ 99 h post-admission were significant for mild elevations of 4-HMP and hydroxy-hexanoic and hydroxy-hexenoic acid species with a notable absence of ketones. Previously, biochemical abnormalities in urine have been shown to normalize in as few as 27 h after treatment giving providers a narrow window with which to obtain a critical sample. Direct communication of laboratory findings to the ordering provider guided the molecular testing and assisted in results interpretation to confirm the molecular diagnosis. Our case emphasizes the importance of collecting samples for biochemical analysis even if the critical period has been missed and acute metabolic decompensation seems to be resolved, as residual abnormalities observed in our patient greatly narrowed the differential diagnosis.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:38

Enthalten in:

Molecular genetics and metabolism reports - 38(2024) vom: 15. März, Seite 101062

Sprache:

Englisch

Beteiligte Personen:

Williams, Monika [VerfasserIn]
Menkovic, Iskren [VerfasserIn]
Reitnauer, Pamela [VerfasserIn]
Gilbert, Eileen [VerfasserIn]
Koeberl, Dwight [VerfasserIn]
Young, Sarah P [VerfasserIn]
Stiles, Ashlee R [VerfasserIn]

Links:

Volltext

Themen:

4-hydroxy-6-methyl-2-pyrone
Case Reports
HMG-CoA synthase deficiency
Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency
Non-ketotic hypoglycemia
Urine organic acids

Anmerkungen:

Date Revised 13.03.2024

published: Electronic-eCollection

Citation Status PubMed-not-MEDLINE

doi:

10.1016/j.ymgmr.2024.101062

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369588266