الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
GD is an autosomal recessive inherited genetic disease. It is progressive and clinically heterogeneous disorder that usually involves multiple body systems. It is the most common lysosomal storage disorder caused by defective activity of the lysosomal enzyme glucocerebrosidase, leading to progressive accumulation of glycolipid glucocerebroside in lysosomes. Tissue macrophages (Gaucher cells) accumulate in multiple organs including bone marrow, liver, spleen, CNS and lung causing the manifestation of the disease.
The aim of this work was to study IgG subclasses in twenty patients, previously diagnosed with GD, presented to the genetics outpatient clinic of Alexandria university children hospital during the period between 2000 and 2016, and to find a relationship-if any- between increased susceptibility to infection in those patients and their IgG subclasses levels.
The findings of the study were as follow:
• Positive family history was reported in 25 % of patients, consangeous marriage was reported in 45% of patients, and the average age of disease presentation was 1 year.
• At diagnosis all patients had low B.glucosidase, high chitotriosidase and normal Sphingomylinase activity.
• The genotype L444P/L444P was reported in (50%) of cases and had higher incidence of positive family history than other types.
• The main presenting symptoms of GD were; abdominal enlargement (100%), pallor (65%), growth retardation (15%).
• 100% of GD patients had repeated respiratory tract infections (more than 4 times /year).
• 10% of the patients had severe thrombocytopenia, 25% had moderate thrombocytopenia and 65% had mild to normal thrombocytopenia. The Platelet count was directly proportionate to B.glucosidase activity and inversely related to chitotriosidase activity.
• Patients with L444P/L444P genotype had a relative higher phosphorus serum levels compared to other genotypes. The type (3) GD patients had a higher calcium serum levels than patients with type (1) GD.
• The neurological evaluation of patients revealed that, 50% of the patients had delayed developmental milestone, 25% of the patients had subnormal intellectual skills, 35% of the patients had abnormal speech pattern, and 30% of the patients had oculomotor apraxia. 20% of patients had squint, 20% of patient had chocking attacks, 25% of patients had trismus of the mandible, 35% of patients had head nodding and convulsions was reported in 15% of patients.
• All cases had osteopenia or osteoporosis of which 30% only manifested by skeletal deformity; 20% of which had dorso-lumbar kyphoscoliosis and 10% had Erlenmeyer flask deformity. Type (3) GD had a higher percent of deformity than type (1) GD.
• 55% of patients (11 cases) had IgG hyperimmunoglobulinemia, 35% (7 cases) had IgE hyperimmunoglobulinemia, 30% (6 cases) had IgM hyperimmunoglobulinemia and 5% (1 case) had IgA hyperimmunoglobulinemia.
• There was no significant difference between GD cases and control group as regard IgG1 or IgG4 levels. IgG2 level was lower in GD cases as compared to control group. IgG3 level was higher in GD cases as compared to control group. There was no significant differences were detected in IgG1, IgG2, IgG3 and IgG4 levels between cases of GD in respect to phenotypes or genotypes of GD. There was also no significant difference between recently treated patients and those who were long treated according to different IgG levels.
• IgG2 hypo-immunoglobulinemia detected in those GD patients was suggested to be the cause for increased rate of respiratory tract infections in those patients. IgG3 hyperimmunoglobulinemia may be a compensatory or a consequence of stimulation from repeated respiratory tract infections that could explain the positive correlation detected between IgG3 and number of infections per year.