GJB6 and myeloid sarcoma: In actively demyelinating lesions, 15 of 24 (62.5%) lesions were classified as pattern A or B, while seven of 17 (41.2%) chronic active lesions showed pattern A or B. None of 10 chronic inactive lesions had pattern A or B. Cx30 expression levels were very low in the astrocytes of MS lesions, similar to levels in the white matter of normal controls (data not shown).