Authors' Reply Obessive-compulsive Disorders Due to Neuroacanthocytosis Treated with Citalopram

We thank R. Walker and A. Danek for their letter emphasizing that the term neuroacanthocytosis is used for distinct diseases, which can be differentiated by means of genetic tests. Our patient [2] suffered from chorea-acanthocytosis. The most prominent differential diagnosis of chorea-acanthocytosis is the McLeod syndrome, which shows a reduction of all Kell antigens and absence of Kx antigen [1] [3]. In our patient no abnormalities of Kell antigens was detected; therefore, this important differential diagnosis can be excluded.

In addition to oral and perioral dyskinesias with self-mutilation of mucosa and lips, the patient had additional findings, including atrophy of caudate nuclei in brain MRI, clinical and electrophysiological signs of peripheral neuropathy, an elevated creatinine kinase and liver abnormalities (with normal serologic tests for viral causes and unspecific biopsy results). Lipoproteins were normal as was coeruloplasmin level and copper excretion. The patient had no seizures, and EEG was normal.

While all of this may be found in both chorea-acanthocytosis and McLeod Syndome, the whole spectrum might be rarely present in other disorders. Serologic exclusion of McLeod syndrome led us to accept the diagnosis of chorea-acanthocytosis, especially, since in our patient the most impressive presenting symptom was his orofacial and lingual dyskinesias [4].

References

• 1 Allen FH, Krabbe SM, Corcoran PA. A new phenotype (McLeod) in the Kell blood-group system.  Vox Sang. 1961;  6 555-560
• 2 Habermeyer B, Fuhr P, Hiss B. et al . Obessive-compulsive disorders due to neuroacanthocytosis treated with citalopram.  Pharmacopsychiatry. 2006;  39 193-194
• 3 Russo D, Redman C, Lee S. Association of XK and Kell blood group proteins.  J Biol Chem. 1998;  273 13950-13956
• 4 Walker RH, Danek A, Dobson-Stone C. et al . Developments in neuroacanthocytosis: Expanding the spectrum of choreatic syndromes.  Mov Disord. 2006;  , Sep 6; [Epub ahead of print]

Correspondence