Central ray deficiency with extensive syndactyly: a dilemma for classification.

Split Hand Foot Malformation (SHFM) (cleft hand/foot, central ray deficiency) is a complex, highly variable anomaly involving the hands and/or feet. A clinical epidemiologic study of split hand/foot (central ray deficiency) of the Manitoba population identified a subset of patients who did not present with either typical or atypical split hand. Clinically, some patients presented with "mitten hand" syndactyly; the deficiency was not recognized before imaging. In this paper, we identify additional similarly affected literature cases, review existing classifications of split hand and syndactyly and attempt to classify these patients. This group presents a challenge for classification and genetic counseling. General classifications permit inclusion of patients with diverse phenotypes; however, details are overlooked. Osseous fusions and disorganization of osseous components complicate classification. Many of these patients had findings that overlapped different subtypes within existing classifications. This cohort highlights the importance of imaging patients with distal limb anomalies. An effective classification scheme should include relevant clinical and radiographic findings in order to assist clinicians following these patients.