Mặc dù khởi đầu thường là trong thập kỷ thứ hai của cuộc sống, các kiểu hình khác nhau. 17. Một cậu bé 10 tuổi trình bày với một lịch sử 1 năm khó khăn ở trường, các vấn đề hành vi, và dáng đi không vững. Ông là sản phẩm của thời kỳ thai nghén bình thường và giao hàng và đạt cột mốc đầu tiên của ông tại thời điểm thích hợp. | 17 asymptomatic mutation-positive patients is not known. Without clinical and genetic evaluation it cannot be known if the sister has inherited the affected gene. Although the onset is usually in the second decade of life phenotypes vary. 17. A 10-year-old boy presents with a 1-year history of difficulties in school behavioral problems and unsteady gait. He was the product of a normal gestation and delivery and reached his early milestones at the appropriate time. Over the last year he has become more withdrawn and has failed several of his classes at school. Previously he was a good student. He has been previously healthy and takes no medications. Family history reveals that his father had some form of a progressive mental illness with shaking and committed suicide at age 42. Numerous relatives on his paternal side were institutionalized in middle age for mental disease several of whom died of suicide. There is no maternal family history of neurological or psychiatric illness. On examination he is distractible and scores 20 30 on the Mini-Mental Status Examination. He has a masked face and reduced eye blink. His gait is bradykinetic. There is diffuse rigidity in the axial musculature and extremities. He has diffuse hyperreflexia and bilateral Babinski signs. MRI of the head is normal. Genetic testing reveals 110 CAG repeats in a gene on . In addition to demonstrating anticipation the inheritance of this patient s disease is also an example of which of the following A. Autosomal recessive inheritance B. Probable nonpaternity C. Parent-of-origin effect D. Expansion of a gene in a noncoding region E. X-linked dominant inheritance Correct Answer The correct answer is C. This patient has the juvenile Westphal variant of Huntington s disease HD . This disorder results from increased numbers of CAG repeats coding for glutamine in the coding region of a gene on coding for the huntingtin protein. The larger the repeat expansion the earlier and more severe the
