In the December 2002 issue of the Journal, in the article entitled, “3-Methylglutaconic Aciduria Type I Is Caused by Mutations in AUH,” by IJlst et al. (71:1463–1466), we reported the molecular basis of 3-methylglutaconic aciduria type I. One of the patients mentioned in our paper was the younger of two affected brothers of healthy nonconsanguineous Moroccan parents. He had no physical abnormalities; only his speech development was retarded. In our report, mutation analysis of the patient’s AUH gene at the cDNA level revealed a homozygous c.589C→T nonsense mutation, whereas PCR-RFLP analysis with NdeI showed an apparent heterozygous mutation at the genomic DNA level. Recently, we have changed to sequence analysis at the genomic level for this disorder. When we reinvestigated this patient using a new primer set (In5AUHrM13NdeI: 5′-cag gaa aca gct atg acc CAT ATG ACC ATT AGG ACC AAC AAG TG-3′ and In4AUHf-21M13: 5′-tgt aaa acg acg gcc agt ATC GTA GAA CTG TGA TTC TG-3′), we found homozygosity for the c.589C→T nonsense mutation. Moreover, sequence analysis of the RFLP-PCR fragment (fig. 3B in our report) also revealed homozygosity for this mutation. Therefore, the apparent heterozygosity at the genomic level reported in our original paper must have been due to partial digestion by the restriction enzyme.
In conclusion, our data demonstrate that the c.589C→T nonsense mutation in the Moroccan patient is homozygous. We regret the error.