The nonsense mutation p.Y322* (c.966C > A) in the ERCC8 gene was found at a homozygous state in patient A who presents with CS type I, which correlates with a published genotype-phenotype study showing that the majority of patients with ERCC8 mutations (75% of CSA patients) are classified as CSI [10]. The gene discussed is ERCC8; the disease is chromosome-type aberration frequency.