Figure 3. ALK-1 gene mutation and protein expression. (a) Exon 10 sequencing results of gene ALK-1. (upper) The result of a normal control; (lower) the result of the patient in this family. The arrowhead indicates the mutation base. This is a C-to-T mutation in base 1717 of ALK-1 gene (1717C>T). This mutation resulted in an amino acid change, from Arg to stop codon (R479X) in the ALK-1 protein. (b) Western blotting verified that the ALK-1 protein was truncated. The protein was isolated from immortalized cells from both patients and normal family members. Lane 1 indicates the patient’s sample, and lane 2 is the sample from a normal individual. A smaller band in the ALK-1 protein from the patient’s sample indicates the truncated ALK-1 protein. The small band was not found in the sample from the normal individual. There were no significant differences in the protein expression levels of ALK-1 (-tubulin, the internal control).