ZFHX3 and spinocerebellar ataxia type 4: Recently, exonic GGC repeat expansion in ZFHX3 has also been described to be associated with the previously molecularly undiagnosed SCA4.32, 35 These disorders join the ranks of NIID to form a new disease entity of polyglycine disorders.65 66 Understanding these disorders collectively is important as they are typically adult-onset, slowly progressive conditions with overlaps in clinical presentation, such as a similar pattern of weakness seen in a large proportion of East Asian individuals with NOTCH2NLC-repeat-positive NIID as individuals with OPDM.