Fahr Syndrome, Hypoparathyroidism and Mitochondrial Encephalomyopathy With Lactic Acidosis and Stroke-Like Episodes...

We describe a 5-year-old boy with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome presenting with epilepsy, refractory hyperlactatemia, and profound hypoparathyroidism accompanied by Fahr syndrome-like brain calcifications. This case expands the known phenotypic spectrum of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome by demonstrating concurrent parathyroid dysfunction and basal ganglia calcifications. The objective of this report is to characterize this unique neuroendocrine presentation and highlight diagnostic considerations for similar cases.

A previously healthy 5-year-old boy presented with 2 days of vomiting, diarrhea, and 1 generalized tonic-clonic seizure. Examination revealed lethargy, positive Chvostek sign, and positive Trousseau sign. Laboratory results showed plasma-free calcium 0.98 mmol/L (reference range, 1.15-1.33), lactate 6.0 mmol/L (reference, 0.7-2.1), and parathyroid hormone 6.62 pg/mL (reference, 12-65). Brain imaging demonstrated symmetrical basal ganglia calcifications. Treatment included levetiracetam, calcium and vitamin D supplementation. Genetic testing confirmed mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome with m.3243A>G mutation. Follow-up showed persistent hyperlactatemia (peak 8.4 mmol/L) and worsening hypoparathyroidism (parathyroid hormone <3 pg/mL).

The severity and persistence of parathyroid hormone suppression in this case contrasts with typical mitochondrial disorder presentations. The concurrence of Fahr-type calcifications and profound hypoparathyroidism suggests potential mitochondrial dysfunction in calcium-regulating tissues.

This case illustrates a severe neuroendocrine phenotype of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome. Unexplained hypoparathyroidism with basal ganglia calcifications should prompt consideration of mitochondrial disorders, even without classic stroke-like episodes.