Assessment of Neurological Manifestations in Gaucher Disease Patients Attending Assiut University Children's Hospital

Gaucher disease, the most common lysosomal storage disorder, caused by reduced activity of acid β-glucosidase and mutations in the GBA1 gene. This leads to the accumulation of its normal substrate, glucocerebroside, in tissue macrophages, affecting the hematological, visceral, bone and neurologic systems. The determination of deficient β-glucocerebrosidase activity in leukocytes or fibroblasts by enzymatic assay is the gold standard for the diagnosis of Gaucher disease. Clinically, Gaucher disease is classified into three major forms based upon the absence or presence and rate of progression of neurological manifestations : type 1 (non-neuronopathic), type 2 (acute neuronopathic), and type 3 (subacute neuronopathic). The nGD forms are Gaucher disease type 2 (GD2) and Gaucher disease type 3 (GD3). GD2 is the acute neuronopathic form and has an early onset CNS involvement, typically manifesting in the first 6 months of life and leading to death by age 2 years, although patients may live up to age 4 years or beyond with supportive medical care. GD3, or the chronic neuronopathic form, has a slightly later onset, CNS symptoms typically manifesting months to years after birth, and has a much slower neurological progression than is seen in GD2. GD3 is the predominant form of Gaucher disease. Phenotypically, there is a wide spectrum of visceral and neurological manifestations. Enzyme replacement therapy has been shown to be effective in reducing glucocerebroside storage burden and diminishing the deleterious effects caused by its accumulation. Enzyme replacement is effective in managing the visceral disease; however, treating the neurological manifestations has proved to be more challenging. Currently, there is no agreement on a definition of nGD, other than one by exclusion ("the presence of neurological involvement in a patient with biochemically proven Gaucher disease, for which there is no explanation other than Gaucher disease")