In spite of extensive search, we did not observe additional INTS8 mutations in other individuals with similar combination of PNH and cerebellar hypoplasia, which suggests that either this association of brain malformations is not constant in this disorder or this is an ultra-rare disorder (i.e. caused by mutation in a gene with very low mutational rate) [47]. The gene discussed is INTS8; the disease is paroxysmal nocturnal hemoglobinuria.