Mitochondrial Complex III Deficiency with Ketoacidosis and Hyperglycemia Mimicking Neonatal Diabetes

Natascia Anastasio; Maja Tarailo-Graovac; Reem Al-Khalifah; Laurent Legault; Britt Drogemoller; Colin J D Ross; Wyeth W Wasserman; Clara van Karnebeek; Daniela Buhas

doi:10.1007/8904_2016_557

Mitochondrial Complex III Deficiency with Ketoacidosis and Hyperglycemia Mimicking Neonatal Diabetes

JIMD Rep. 2017:31:57-62. doi: 10.1007/8904_2016_557. Epub 2016 Apr 14.

Authors

Natascia Anastasio¹, Maja Tarailo-Graovac², Reem Al-Khalifah^{3

4}, Laurent Legault³, Britt Drogemoller⁵, Colin J D Ross⁶, Wyeth W Wasserman⁷, Clara van Karnebeek⁸, Daniela Buhas⁹

Affiliations

¹ Department of Medical Genetics, McGill University, 1001 Boulevard Décarie, Montréal, QC, Canada, H4A 3J1. [email protected].
² Centre for Molecular Medicine and Therapeutics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada, V5Z 4H4.
³ Division of Pediatrics Endocrinology, McGill University, 1001 Boulevard Décarie, Montréal, QC, Canada, H4A 3J1.
⁴ Division of Pediatric Endocrinology, King Saud University, Riyadh, Saudi Arabia.
⁵ Child & Family Research Institute, University of British Columbia, 938 West 28th Avenue, Vancouver, BC, Canada, V5Z 4H4.
⁶ Child & Family Research Institute, University of British Columbia, 950 West 28th Avenue, A3-216, Vancouver, BC, Canada, V5Z 4H4.
⁷ Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, Child & Family Research Institute, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada, V5Z 4H4.
⁸ Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, Child & Family Research Institute, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada, V5Z 4H4.
⁹ Department of Medical Genetics, McGill University, 1001 Boulevard Décarie, Montréal, QC, Canada, H4A 3J1.

Abstract

Hyperglycemia is a rare presenting symptom of mitochondrial disorders. We report a case of a young girl who presented shortly after birth with ketoacidosis, hyperlactatemia, hyperammonemia, and insulin-responsive hyperglycemia. Initial metabolic work-up suggested mitochondrial dysfunction. Given our patient's unusual presentation, whole-exome sequencing (WES) was performed on the parent-offspring trio. The patient was homozygous for the c.643C>T (p.Leu215Phe) variant in CYC1, a nuclear gene which encodes cytochrome c ₁ , a subunit of respiratory chain complex III. Variants in this gene have only been previously reported in two patients with similar presentation, one of whom carries the same variant as our patient who is also of Sri Lankan origin.Primary complex III deficiencies are rare and its phenotypes can vary significantly, even among patients with the same genotype.

Keywords: CYC1 variant; Complex III; Neonatal diabetes; Whole-exome sequencing (WES).