The statistical analysis of phenotypic data available on 180 cases of the Brachmann-de Lange syndrome (BDLS), (161 previously published, 19 personally studied) documented the incomplete nature of most case reports, and the fact that investigators are more likely to mention abnormal traits than normal traits in their reports; it did not uncover evidence of (etiologically pertinent) heterogeneity of the BDL phenotype. The finding of a C-autosomal ring in one of our patients and the available genetic and cytogenetic data are discussed in the context of the hypothesis that the BDLS is recessively inherited and that the homozygous state of this incompletely recessive gene predisposes to early zygotic chromosome breakage and/or chromosome loss which is lethal in most cases. The hypothesis of autosomal recessive inheritance is further strengthened by the discovery of a new BDL case (PM) at Central Wisconsin Colony in Madison (courtesy Dr. E. G. Kaveggia); this 35-year-old woman was the product of an uncle/niece marriage.