To report two individuals with Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome who presented with a metabolic stroke, which has rarely been described as a clinical manifestation of this syndrome.
ZTTK syndrome is a rare condition caused by a loss-of-function mutation in the SON gene, which is located in chromosome region 21q22, and there are approximately 60 known cases.1 The SON gene is involved in cellular and mitochondrial processes, but much is still unknown.2,5,6 The commonly associated clinical manifestations of this condition are global developmental delay, dysmorphic facial features, musculoskeletal abnormalities, abnormal brain MRI, hypotonia, eye anomalies, seizures, and short stature.1 Here we report two individuals who presented to our institution with a metabolic stroke, which has rarely been described previously other than a single reported case.3 As ZTTK syndrome remains a rare disease, reports which expand the clinical phenotype will help inform clinicians of previous findings, diagnoses, and management strategies.
Case series
Two female children, 11 and 12-year-old, presented very similarly to our institution with sudden left hemiparesis and right gaze preference. Both girls carried a diagnosis of ZTTK syndrome based on their clinical characteristics and genetic testing. Both girls were found to have a metabolic stroke on their MRI brain after extensive workup. The 12-year-old girl was treated with L-arginine, levocarnitine, and ubiquinone, which has been used to treat metabolic strokes in mitochondrial disorders. The 11-year-old girl did not receive any particular treatment for stroke. Both individuals returned to their previous functional baseline within two weeks.
Metabolic stroke is a rare clinical manifestation of ZTTK syndrome. It is important to recognize metabolic stroke as an etiology of sudden hemiplegia in ZTTK syndrome as it carries clinical and therapeutic implications. Further studies are needed to determine the cause of metabolic stroke in this syndrome.