Phenotypic Spectrum of Type 2-3 Gaucher Disease: A Case Study in the Balkan Genotype.

BACKGROUND Gaucher disease (GD) is a lysosomal storage disorder caused by mutations in the glucosylceramidase beta 1 (GBA1) gene, with a wide range of clinical manifestations. Type 2 GD, the acute neuronopathic form, is the most severe and has historically been considered a distinct clinical entity. Emerging evidence suggests a broader phenotypic spectrum, including intermediate forms that do not fully align with the diagnostic criteria for either type 2 or type 3 GD. Here, we describe an Albanian patient with an unusual intermediate type 2-3 phenotype, homozygous for the rare GBA1 complex allele p.[His294Gln;Asp448His] that is frequently found in Balkan populations. Although this genotype is typically associated with early-onset type 2 GD and death within the first 2 years of life, our patient developed neurologic symptoms at 15 months and survived until age 5. CASE REPORT A male Albanian infant presented at 4 months of age with hepatosplenomegaly and thrombocytopenia. Genetic testing revealed homozygosity for the rare GBA1 complex allele p.[His294Gln;Asp448His]. Enzyme replacement therapy, initiated at 7 months, led to temporary improvement of visceral and hematological symptoms. Neurologic manifestations - including oculomotor apraxia, dystonia, and seizures - emerged at 15 months. Despite continued enzyme replacement therapy and supportive care, the patient's neurologic condition progressively worsened, and he died at age 5 due to disease progression and pulmonary complications. CONCLUSIONS This case reinforces the concept that type 2 GD exists on a phenotypic spectrum, rather than as a uniform clinical entity, and underscores the broad genotype-phenotype variability in GD.