An Unusual Seizure Presentation in Early-Onset Alpers–Huttenlocher Syndrome

DNA polymerase gamma-1 (POLG)-related disorders have a varying age of onset, different modes of inheritance, and a wide array of symptoms. Alpers–Huttenlocher syndrome (AHS) is the most severe subtype, with an autosomal recessive mode of inheritance. It can be caused by either homozygous or compound heterozygous mutations of the POLG gene. Both sexes are apparently equally affected and early-onset cases present between 2 and 4 years of age. Diagnostic criteria include refractory seizures, hepatopathy, and psychomotor regression, with or without additional findings such as certain abnormal electroencephalogram (EEG) findings, elevated blood/ cerebrospinal fluid lactate levels, myopathy, and/or a sibling with a confirmed diagnosis of AHS. Diagnosis is confirmed via POLG sequencing, liver biopsy, or (rarely, today) autopsy. Here, we present a case of AHS with an unusual presentation of abnormal, repetitive, one-sided neck movement, abnormal hand movement, and rolling back of the eyes, in a 4-year-old boy. His EEG findings, routine blood tests, and metabolic profile were within normal limits. Diagnosis of AHS was confirmed by targeted DNA sequencing, revealing a homozygous variant of POLG (c.3286C>T; p.Arg1096Cys), the same as that found in his deceased elder sister.
 

Author(s):

Mohammed Almuqbil

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