Abstract: Objective　To report clinical manifestations, electroencephalogram (EEG), and the genotypes of two siblings with type Ⅲ Gaucher disease. Methods　Two patients with different features were siblings. Their clinical data, signs, peripheral leukocytes acid β-glucosidase activity, and GBA gene were analyzed. Results　(1) The proband was a boy. He visited us at the age of nine years old because of hepatosplenomegaly, thrombocytopenia and growth retardation without any neurologic symptoms. He had normal intelligence but abnormal EEG findings. The activity of acid β-glucosidase in his leucocytes decreased to 1.5 nmol h-1·mg-1 Pr (normal range 6.0-16.7 nmol h-1·mg-1 Pr), supporting the diagnosis of type Ⅲ Gaucher disease. (2) The elder sister of the proband was 12 years old. She had tonic-clonic seizure and myoclonus seizure from the age of seven years old. Mild hepatomegaly, abnormal EEG, poor effect for antiepileptics, and progressive deterioration of psychomotor abilities were found. Her blood leucocytes acid β-glucosidase activity decreased to 1.8 nmol h-1·mg-1 Pr (normal range 6.0-16.7 nmol h-1·mg-1 Pr). Two heterozygous missense mutations, c.680A>G, (p.N188S) and c.1342G>C (p.D409H) were detected from the two siblings, respectively. Conclusions　Patients with type Ⅲ Gaucher disease usually have the onset in childhood with typical features of Gaucher disease without neurologic involvement. Abnormal EEG may be helpful to the differential diagnosis of type I or type Ⅲ . On the other hand, neurologic manifestations could be presented as the first symptom in some patients without viscera enlargement. The patients of type Ⅲ Gaucher disease with the same genotype could have different phenotypes, even between the siblings.