Pseudohypertriglyceridemia: A Novel Case with Important Clinical Implications

Pseudo-hypertriglyceridemia in a 2-year-old male with global developmental delay, myopathy and adrenal hypoplasia

Pseudo-hypertriglyceridemia is an overestimation of serum triglyceride levels due to laboratory assays that measure free glycerol concentrations instead of triglycerides directly. Consequently, conditions presenting with elevated levels of endogenous or exogenous free glycerol, such as glycerol kinase deficiency, result in an overestimation of serum triglycerides. Glycerol kinase deficiency (GKD) is caused by pathogenic variants of the GK gene on chromosome Xp21. GKD is characterized biochemically by hyperglycerolaemia and glyceroluria. We herein report a 2-year-old male presented with a history of global developmental delay, axial hypotonia, poor head control and inability to sit unassisted or walk with elevated triglycerides at 683 (normal 44-157 mg/dL). Organic acid analysis showed abnormal accumulation of glycerol. Chromosomal microarray results showed a 4.2 Mb deletion of Xp21.3p21.1 (29296579-33551038) including complete copies of GK, DMD, and NR0B1 genes as well as multiple exons of IL1RAPL1. This confirmed his glycerol kinase deficiency (GKD) as part of the Xp21 continuous gene deletion syndrome. Elevated triglycerides were then recognized as pseudo-hypertriglyceridemia after the diagnosis. The younger sister and the mother have presented with developmental delay, and have been found to have same mutation. This family highlights the importance recognizing pseudohypertriglyceridemia and diagnostic challenges. Earlier identification through urine organic acid analysis could have been made. The combination of clinical presentations and increased glycerol should cause suspicion for GKD.

Severe glycerol intoxication mimicking toxic alcohol ingestion following large volume consumption of vanilla essence

INTRODUCTION

Patients with ethanol dependence may consume vanilla extract for the high alcohol content.

CASE PRESENTATION

A 42-year-old male with ethanol dependence who developed status epilepticus, severe anion gap metabolic acidosis and a hyperosmolar non-ketotic coma after ingestion of 600 mL vanilla essence. He was found to have an osmolar gap of 151 with a marked pseudohypertriglyceridaemia of 96.4 mmol/L (8350 mg/dL), found to be secondary to significantly elevated glycerol levels. The patient required intubation for status epilepticus and dialysis to correct the severe acid-base disturbance and remove excess glycerol. The patient made a full recovery.

DISCUSSION

Glycerol is traditionally thought to be a nontoxic alcohol, but this represents a severe case of glycerol toxicity requiring treatment with dialysis. It may represent an emerging or underdiagnosed clinical presentation given availability of high-glycerol products. In the right clinical context, pseudohypertriglyceridaemia and altered mental state may be recognised as glycerol intoxication, avoiding the need for unnecessary investigations.

A rare co-occurrence of duchenne muscular dystrophy, congenital adrenal hypoplasia and glycerol kinase deficiency due to Xp21 contiguous gene deletion syndrome: case report

BACKGROUND

Contiguous gene deletion syndromes are rare genomic disorders caused by deletion of large segments of DNA resulting in co-occurrence of apparently unrelated multiple clinical phenotypes. We report a boy with contiguous gene deletion involving Xp21 genomic location.

CASE PRESENTATION

A Sri Lankan boy with developmental delay and failure to thrive first presented at three years of age with hypovolaemia, hyperpigmentation and drowsiness. Investigations done at that time revealed hypoglycaemia, hyponatraemia, hyperkalaemia, low cortisol, low aldosterone, high ACTH and low 17-hydroxyprogesterone. He was diagnosed to have primary adrenal insufficiency. During follow-up at five years, he was noted to have progressive difficulty in walking, waddling gait, hypotonia, calf hypertrophy and positive Gower's sign. His creatine kinase was very high, and the electromyogram showed myopathy. Genetic analysis revealed hemizygous deletion involving the final 35 exons of the dystrophin gene confirming the diagnosis of Duchenne muscular dystrophy. Further investigations revealed pseudohypertriglyceridemia, large glycerol peak on urine organic acid analysis and hemizygous deletion of the glycerol kinase gene confirming glycerol kinase deficiency. Based on the presence of Duchenne muscular dystrophy, glycerol kinase deficiency and probable congenital adrenal hypoplasia along with genetic confirmation of deletions involving dystrophin and glycerol kinase genes, the diagnosis of Xp21 contiguous gene deletion syndrome was made.

CONCLUSIONS

We report a child with contiguous gene deletion syndrome who was initially diagnosed as having isolated primary adrenal insufficiency probably due to congenital adrenal hypoplasia. Later he was confirmed to have Duchenne muscular dystrophy and glycerol kinase deficiency, as well. This case report highlights the importance of pre-emptive evaluation and identification of genetic defects when patients present with seemingly unrelated diseases that could aid in accurate diagnoses of contiguous gene deletion syndromes.