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Mitochondrial 3-hydroxymethylglutaryl-CoA synthase-2 (HMGCS2) deficiency: a rare case with bicytopenia and coagulopathy
  1. Dalia El-Sayed1,
  2. Hanaa El-Karaksy1,
  3. Yasser Wali2,3 and
  4. Ilham Youssry1
  1. 1Pediatrics, Cairo University Kasr Alainy Faculty of Medicine, Cairo, Egypt
  2. 2Department of Child Health, Sultan Qaboos University, Muscat, Oman
  3. 3Alexandria University Faculty of Medicine, Alexandria, Egypt
  1. Correspondence to Dr Yasser Wali; yasser_wali{at}


Mitochondrial 3-hydroxymethylglutaryl-CoA synthase-2 (HMGCS2) is the main enzyme involved in ketogenesis. It is an essential enzyme for the catalysis of β-oxidation-derived-acetyl-CoA and acetoacetyl Co-A to produce β-hydroxy-β-methylglutaryl-CoA (HMG-CoA) and free coenzyme A.

The deficiency of this enzyme (3-hydoxy-3-methylglutaryl-CoA synthase) is a very rare metabolic disorder with limited cases described in the literature. The manifestations of this disease include hypoketotic hypoglycaemia, metabolic acidosis, lethargy, hepatomegaly with fatty liver and encephalopathy.

We report a middle childhood male who presented with hepatosplenomegaly, lymphadenopathy and bicytopenia. The case was diagnosed by the whole exome sequencing which revealed a homozygous missense variant of uncertain significance in HMGCS2 gene.

  • Haematology (incl blood transfusion)
  • Metabolic disorders

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  • Contributors The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: DE-S, HE-K, YW, IY. The following authors gave final approval of the manuscript: DE-S, HE-K, YW, IY.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.