Objective: Objective: To demonstrate the importance of serum biomarkers, such as alpha-fetoprotein (AFP), in the diagnostic evaluation of Ataxia with Oculomotor Apraxia Type 2 (AOA2).

Background: Background: AOA2 is an autosomal recessive cerebellar ataxia caused by biallelic mutations in the SETX gene (9q34), with a diagnosis confirmed through genetic analysis. Serum biomarkers, such as AFP, also play an important role in raising diagnostic suspicion.

Method: Methods: This case report discusses a patient from Professor Edgar Santos University Hospital in Salvador, BA. Data was gathered from the patient’s electronic medical record. Genetic analysis was performed using the OMIM platform, and PubMed searches were conducted to review related scientific articles, enhancing understanding of the genetic conditions and their clinical implications.

Results: Results: We present the case of a 19-year-old female patient, the daughter of consanguineous parents, who initially exhibited mild thoracic curvature, nonspecific gait and hand abnormalities in childhood. During adolescence, she experienced worsening motor coordination and balance, leading to difficult walking, frequent falls, and problems handling objects, which ultimately required assistance with daily activities. She also reported dysarthria and difficulty swallowing liquids. Physical examination revealed multidirectional horizontal and vertical nystagmus, hypometric saccades, prominent decomposition of pursuit movements, and ocular apraxia. Muscle strength was globally preserved, with mild hypotonia, absent deep tendon reflexes, and reduced vibration sense in the lower limbs were noted. The patient showed gait and appendicular ataxia, with rebound phenomenon, dysmetria, intention tremor, and bilateral dysdiadochokinesia. Complementary exams revealed elevated total cholesterol (128mg/dL), increased AFP (41.7 IU/mL), cerebellar atrophy on brain magnetic resonance imaging, and findings suggestive of axonal neuropathy on electromyography. Whole-genome sequencing identified a variant of uncertain significance (VUS) c.5890C>T:p.(Pro1964Ser) in exon 14 of the SETX gene in the homozygous state.

Conclusion: Conclusion: Despite the high utility of genetic testing, serum biomarkers like AFP, which are more accessible and provide faster results, combined with the clinical picture, can strengthen the diagnostic suspicion even when genetic findings are inconclusive or unavailable.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/a-vus-and-the-value-of-a-biomarker-in-ataxia-with-oculomotor-apraxia-type-2/