Squares indicate male subjects, and circles female subjects. Black denotes affected subjects, and white unaffected subjects; gray indicates that the status of the subject is unknown. A slash through the symbol indicates that the subject is deceased. The gene for atrial natriuretic peptide (NPPA) is located at 1p36-p35. Markers that were tested for this region of chromosome 1 are listed in order from the p-terminal end of the chromosome, with map locations according to the Web site of the National Center for Biotechnology Information (www.ncbi.nlm.nih.gov) and given in megabases and centimorgans. A common c.454C→T polymorphism in exon 3 of wild-type NPPA is included, along with the NPPA mutation (NPPA mut). The haplotypes for these markers are shown in columns beneath family members who underwent genetic evaluation; the disease-associated haplotypes are boxed. Two subjects (III-7 and III-9) inherited portions of the disease haplotype, but not the disease gene, as a result of recombination events.