Clinical Phenotype of FASTKD2 Mutation

Area of Science:

• Genetics
• Neurology
• Pediatrics

Background:

• Mitochondrial disorders (MIDs) are complex genetic conditions affecting multiple organ systems, often leading to significant morbidity and mortality.
• Accurate diagnosis of primary MIDs, caused by mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) gene mutations, has historically been challenging.
• Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is a subtype of MID with characteristic neurological symptoms.

Observation:

• Two siblings presented with recurrent status epilepticus and neurological symptoms suggestive of metabolic or viral encephalitis.
• Initial treatments for status epilepticus were partially effective, but the elder sibling experienced a fatal recurrence.
• Neuroimaging revealed reversible diffusion restriction in specific brain regions, consistent with stroke-like episodes.

Findings:

• Exome sequencing identified a rare variant in the FASTKD2 gene in both siblings.
• This genetic finding confirmed a diagnosis of a specific type of mitochondrial disorder.
• The clinical presentation and neuroimaging findings were consistent with the genetic diagnosis.

Implications:

• This case report underscores the importance of considering rare genetic mutations, such as in FASTKD2, in the differential diagnosis of unexplained neurological emergencies in children.
• Increased clinical awareness of FASTKD2 mutations can lead to earlier diagnosis and potentially improved management strategies for affected individuals.
• Genetic analysis is essential for accurate diagnosis and family counseling in suspected mitochondrial disorders.