The Relativity Study Between Clinical And TTR Gene Mutation Of Familial Vitreous Amyloidosis

To Study clinical and hereditary features of a Han pedigree with familial vitreous amyloidosis in Guizhou province, and the relation between the disease and transthyretin(TTR) gene mutation, and to indicate the locus and type of TTR gene mutation.Methods: We had treated 7 patients(10 eyes) with familial vitreous amyloidosis from same family from July 2007 to February 2008. The preoperative visual acuity was from HM/30cm to 0.2. All cases were administrated surgical operation , 4 cases (6 eyes ) single vitrectomy, 3 cases (3eyes) with intraoperative iatrogenic retinal tear and 1 eye with tracting retinal detachment demonstrated by B-scan ultrasonic were vitrectomy + photocoagulation + gas filling operation, and 1 case(1 eye) len was removed and implanted intraocular lens. The excision of vitreous was stained by Congo red, and postoperative patients were carried out fundus fluorescein angiography(FFA), and followed visual acuity and fundus from 6～12 months. We finished further family genealogical survey and drawed map of family pedigree, 11 individual's peripheral venous blood from identical pedigree's (including 7 case patients, 1 case early vitreous opacities, 1 case symptomless, 1 case patient's spouse and 1 case patient's daughter) were collected and DNA were extracted, 4 exons of TTR gene were amplified by polymerase chain reaction(PCR), the gene fragments were bidirectional sequencing with the fluorescence labelling method. The sequencing result was analyzed with DNAMAN Windows 5.2.2.0 assimilated by the Chinese software and the Chromas sequence chart analysis software, and compared results with normal human TTR gene exons.Results: Congo red staining of the excision of vitreous in 7 cases(10 eyes) was positive. FFA examination: 1 case(1 eye) showed small spot hemorrhage in retina, 1 case(1 eye) showed minor fluorescein leakage in peripheral retinal vascular,the remainer(8 eyes) were normal. The visual acuity was greater or equal to 1.0 in 3 cases (5 eyes), 0.6～0.8 in 3 cases (4 eyes), 0.4 in 1 case (1 eyes), didn't find the vitreous opacity was recurrence in fundus examination. Family pedigree analysis revealed that the patients appeared in three generations , men and women had equal prevalence, one of patient's parents was patient. The age with disease was generally after 35～40 years old. 11 individual TTR gene exons sequencing results were consistent completely with normal human TTR gene. But a C(cytosine) had inserted in all individuals intron 3424 position.Conclusion: Vitrectomy is safety and effective way treating familial amyloid vitreous, and can restore patient's visual acuity and improve patient's quality of life. We find that Han pedigree with familial viteous amyloidosis in Guizhou province is characteristized by autosomal dominant genetic disease, TTR gene exons is not mutation, basic group C insertion in 3424 may be relevance with race or region , also with missing detection of normal humanTTR gene sequence.