Genetic Analysis of Craniofrontonasal Syndrome

The scientific objective of this study is to determine if all patients with Craniofrontonasal Syndrome (CFNS) contain mutations in the ephrin-B1 (EFNB1) gene in Xq12. We will use mutational analysis of EFNB1 as our principal tool to study the genetics of CFNS. Previously, we had mapped the CFNS locus to a 13 cM region in Xp22 using linkage analysis of 12 unrelated CFNS families with 2 or more affected family members in 2-4 generations. More recently there have been two reports that 23 independent CFNS patients all have mutations in the EFNB1 located at Xq12. Hence, either CFNS displays genetic heterogeneity with at least two genes (one in Xp22 and EFNB1) or our previous linkage analysis was inaccurate and all CFNS patients have EFNB1 mutations. We have previously collected a large number of coded blood samples from patients with DFNS. We propose to sequence the EFNB1 in all 12 of our previously published CFNS families as well as 6 additional families, 22 sporadic CFNS patients, and two CFNS patients with chromosomal anomalies. We will be sending letters to all physicians who have referred CFNS patients to us in the past for molecular studies. This letter will outline the recent developments identifying EFNB1 as the CFNS gene. We would like to utilize the referring physicians as liaisons between our lab and CFNS patients. Through the referring physicians, we will invite the patients and their families to join a new study if they are interested in obtaining their genetic testing results. All of our results will be confirmed by a CLIA-certified lab prior to being given to patients or referring physicians.