Other major signs of SCA6 are the loss of vibratory and proprioceptive sensation and nystagmus.While most patients present with these severe progressive symptoms, others, sometimes within the same family, display episodic non-progressive symptoms more similar to episodic ataxia. Still others present with symptoms common to both SCA6 and familial hemiplegic migraine. Pathophysiology
Most cases of SCA6 are a result of CAG repeat expansion beyond the normal range, i.e., more than 19 repeats, in the Cav2.1 calcium channel encoding gene CACNA1A. This gene has two splice forms, "Q-type" and "P-type", and the polyglutamine coding CAG expansion occurs in the P-type splice form. This form is expressed heavily in the cerebellum where it is localized in Purkinje cells. In Purkinje cells from SCA6 patients, mutant Cav2.1 proteins form ovular intracellular inclusions, or aggregations, similar in many ways to those seen in other polyglutamine expansion disorders such as Huntingtons disease. In cell culture models of the disease, this leads to early apoptotic cell death.Mutant channels that are able to traffic properly to the membrane have a negatively shifted voltage-dependence of inactivation. The result of this is that the channels are active for a shorter amount of time and, consequently, cell excitability is decreased.There are also a number of point mutations resulting in patients with phenotypes reminiscent of episodic ataxia and SCA6 (C271Y, G293R and R1664Q) or familial hemiplegic migraine and SCA6 (R583Q and I1710T). C287Y and G293R are both located in the pore region of domain 1 and are present in a single family each.
Autoimmune polyendocrine syndromes (APSs), also called polyglandular autoimmune syndromes (PGASs) or polyendocrine autoimmune syndromes (PASs), are a heterogeneous group of rare diseases characterized by autoimmune activity against more than one endocrine organ, although non-endocrine organs can be affected. There are three types of APS, and there are a number of other diseases which involve endocrine autoimmunity. Types
Autoimmune polyendocrine syndrome type 1, an autosomal recessive syndrome due to mutation of the AIRE gene resulting in hypoparathyroidism, adrenal insufficiency, hypogonadism, vitiligo, candidiasis and others. Autoimmune polyendocrine syndrome type 2, an autosomal dominant syndrome due to multifactorial gene involvement resulting in adrenal insufficiency plus hypothyroidism and/or type 1 diabetes. Immunodysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX syndrome) is X-linked recessive due to mutation of the FOXP3 gene on the X chromosome. Most patients develop diabetes and diarrhea and many die due to autoimmune activity against many organs. Boys are affected, while girls are carriers and might experience mild disease. Cause
Each "type" of this condition has a different genetic cause. IPEX syndrome is inherited in males by an X-linked recessive process. The FOXP3 gene, whose cytogenetic location is Xp11.23, is involved in the mechanism of the IPEX condition. Diagnosis
Diagnosis for type 1 of this condition for example, sees that the following methods/tests are available:
Endoscopic
CT scan
Histologic test

Differential diagnosis
For this condition, differential diagnosis sees that the following should be considered:
CD25 deficiency
STAT5B deficiency
Severe combined immunodeficiency
X linked thrombocytopenia

Management
Immunosuppressive therapy may be used in type I of this condition.