Genetic Mutational Analysis Of Gaucher Disease

Research backgroundGaucher disease?GD?is a rare lysosomal storage disease with autosomal recessive inheritance.It was first proposed by Philippe Gaucher in 1882.It is based on the abnormal accumulation of glucoside in mononuclear macrophages of different tissues and organs.Normally,the degradation of glucocerebroside requires two proteins,glucocerebrosidase?GBA?and protein kinase C.Protein kinase C is an essential activator for the hydrolysis of glucosylceramide by the GBA enzyme,either GBA or Protein kinase C is defective,it will result in a large accumulation of the substrate glucocerebroside.However,the vast majority of Gaucher's disease is caused by the mutation of the GBA gene.Protein kinase C deficiency is a very rare reason.Currently,only 7 cases have been reported worldwide.GBA gene mutation leads to a remarkable decrease in the activity of glucocerebrosidase?GBA?in the body,and glucosylceramide in mononuclear macrophages cannot be efficiently hydrolyzed,which results in a large amount of substrates be stored in the mononuclear-macrophage cells of liver,spleen,bone,bone marrow,lungs and the brain,the clinical manifestations include progressive liver and spleen enlargement,bone involvement,growth retardation,various degrees of anemia,thrombocytopenia,dyspnea,and nervous system disorders.Due to the poor prognosis,it brings much pain to patients and families.Therefore,we summarize the clinical manifestations of the disease and the characteristics of bone marrow cytology,aimed at achieving early detection,early diagnosis and early treatment.At the same time,in order to reduce the occurrence of this type of hereditary disease,we can provide genetic counseling and prenatal diagnosis for their parents.ObjectiveTo summarize the clinical features of three cases of Gaucher disease in three unrelated families,using gene sequencing to study genetic mutation patterns and molecular genetics pattern of Gaucher disease patients,thereby providing genetic counseling and prenatal diagnosis.MethodAfter being informed consent was obtained from the family members of the patient and approved by the Ethics Committee,Collecting the clinical data and peripheral blood samples of 3 patients and other family members.At the same time,20 peripheral blood samples of healthy children were collected as control.The Gene DNA kit was used to extract the genomic DNA of blood samples,and the peripheral blood genomic DNA of 3 patients and their family members was extracted,and the exome gene mutation test was performed using the second generation sequencing method.Then for those mutation sites which had clinical significance,they were verified by the first generation Sanger sequencing?Result 1.In the first family,the gene test found that proband 1 has compound heterozygous nucleotide variation of GBA gene,they are c.1448T> C on exon 11 and c.907C> A on exon 8,Then the results of first generational sequencing showed that there were two heterozygous mutations in the exon of GBA gene in proband 1,which were c.1448T> C on exon 11 and c.907C> A on exon 8.The former was inherited from his father,and the latter was inherited his mother.2.In the second family,the gene test found that proband 2 has compound heterozygous nucleotide variation of GBA gene,they were c.1226A> G on exon 10 and c.1174 del C on exon 9,above all,c.1174 del C is a new mutation,there is no report in the literature previously.The results of the first generation sequencing showed that the proband 2 had two heterozygous mutations in the exon region of GBA gene of Gaucher disease,which were c.1226A> G on exon 10 and c.1174 del C on exon 9.The former was inherited from his father,and the latter was inherited his mother.Besides,the sister of proband also had a mutation of c.1174 del C on exon 9.3.In the third family,gene test found proband 3 has two mutations of GBA gene,one was homozygous nucleotide variation,and the other was Heterozygous nucleotide variation.they were c.1342G> C and c.1263₁317del,both were on exon 10.The first-generation sequencing verification results showed that there was a homozygous mutation and a heterozygous mutation in the exon region of GBA gene of Gaucher-disease-related genes in proband 3,both were located on exon 10,which were c.1342 G > C homozygous nucleotide variation and c.1263₁317del heterozygous nucleotide variation.The former was inherited from his parents,and the latter was inherited his father.Conclusion 1.The probands in the three families met the clinical manifestations,the characteristics of bone marrow cytology,and the types of gene mutations of the Gaucher disease,the diagnosis was clearly.2.The pathogenicity of the c.1174 del C mutation found in proband 2 had not been reported in the literature previously.It is a new mutation which has enriched the domestic research in the field of molecular genetics of Gaucher disease.