Serum ITPR1-IgG/anti-Sj titres in the present patient were clearly positive (1:1000, 1:320, 1:100, respectively) but lower than those reported in two of the three index patients with cerebellar ataxia [1] and two of the three patients with neuropathy described in Ref. The gene discussed is ITPR1; the disease is cerebellar ataxia.