Clinical and MR findings

Case	Age at Onset	Clinical Findings	Location of MRI abnormalities
			Medulla	Inferior Cerebellar Peduncles	Dentate Nuclei	Midbrain				Subthalamic Nuclei	Basal Ganglia
			Medulla	Inferior Cerebellar Peduncles	Dentate Nuclei	Interpeduncular Nucleus	Central Tegmental Tracts	Substantia Nigra	Pallido-cortical/Nigro-cortical Tracts	Subthalamic Nuclei	Basal Ganglia
1	14 m	Neurodevelopmental regression, hypotonia, absent deep tendon reflexes; weight, height, and head circumference < second centile; severe respiratory difficulties; blood lactate at rest: 58 mg/dL (normal 8–22 mg/dL); lactate/pyruvate ratio: 61.6 (normal 6–25); death at age 22 months from cardiorespiratory arrest;	+	+	−	−	+	+	−	+	−
2	12 m	Failure to thrive, neurodevelopmental regression, frequent vomiting, facial dysmorphism, hirsutism, hypotonia; blood lactate at rest: 32 mg/dL (normal 8–22 mg/dL); alive at age 3 years	+(extending to cervical cord)	+	+	−	−	+	−	+	−
3	12 m	Failure to thrive, neurodevelopmental delay; episodes of palpebral ptosis and impaired consciousness; facial dysmorphism, hirsutism, nystagmus, hypotonia, absent deep tendon reflexes, breathing abnormalities; blood lactate at rest: 42 mg/dL (normal 8–22 mg/dL); alive at age 4 years	+	+	+	+	+	+	+	+	+

Note.—m, months; +, present; −, absent.