Clinical Manifestation, Imaging Characteristics, And Gen Mutation Analysis Of One Pedigree Of The Spinocerebellar Ataxia With Severe Cataract

Objective: Spinocerebellar ataxia (SCA) is a rare degenerative disease of thenervous system. The clinical characteristic of this disease is insidious onset, slow inprogress. Usually the patient can’t walk in the10-20years after onset. For the reasonthat the symptom of SCA are varied and completed also there are overlap in thesymptom of different subtypes in SCA,the clinical diagnosis of the SCA is very difficult.Until now the diagnosis of different types of SCA still depends on the clinicalmanifestations mainly, particularly its characteristic clinical findings together withpositive family history. Genetic diagnosis is an important means of diagnosis. A total of35types of SCA were reported now, and a special SCA pedigree with cataract wasfound by us and the main clinical manifestations, image characteristics and genemutation were studied.Methods: The clinical files of the pedigree was collected. The score wasevaluated using International Cooperative Ataxia Rating Scale （ICARS） andmini-mental state examination（MMSE）on the cases and the members without thedisease. MRI was scanned to the cases’ brain, and the image changes of which wasdescribed. The gene detection was conducted by using polymerase chain reaction (PCR)and Agar gel electrophoresis technology on the cases and some healthy subjects in thepedigree.Results: All the six cases manifested as cerebellar ataxia together with severecataracts.3of six members from the2nd generation fell ill, the incidence rate was50%,and the disease was found in both male and female in the pedigree. The mean age of thesix cases was27.3(±3.6) years, in which3dead cases’ average duration was14.0(±1.7) years. The ICARS score of the3existing cases was20points,44points,93pointsrespectively, and the MMSE scores were27points,28points,5points respectively. All the6cases got the disease after20years old,and the average age of onset among thesecond and the third generation from the pedigree were29.3(±0.6) years,25.3(±4.5)years old respectively. The onset period of the3rd generation was earlier than the2nd.Atrophy in the cerebellum and pons was observed in the MRI of the two patients, andthe horizontal position was found in the “midline linear”. After genetic testing, wefound that the number of trinucleotide duplication in the gene encoding region ofSCA1,SCA2,SCA3,SCA6,SCA7,SCA17and DRPLA was normal, the number oftrinucleotide duplication in the3’ none-coding region(CTG)n in SCA8genes wasnormal too, the same as SCA12gene5’ non-coding region (CAG)n.Conclusions:1.Our study discovered a SCA pedigree with severe cataracts fromDalian， showed as dominant inheritance with a characteristic including earlyonset,faster progress, severe cognitive impairment in the advanced stage.2.Ingenetic,the delay dominance and genetic anticipation were obvious, but there was nosignificant genetic heterogeneity.3. In MRI, atrophy in the cerebellum and pons wasobserved, and the horizontal position was found in the “midline linear”.4. No genemutation loci was found no mutations, so we speculated that maybe the type of thepedigree was a new subtype of SCA. On the other hand, it might be a type of knownSCA subtype appearing new accompanying symptoms due to the geneticheterogeneity.