Central ray deficiency with extensive syndactyly: a dilemma for classification

Area of Science:

• Medical Genetics
• Developmental Biology
• Orthopedics

Background:

• Split Hand Foot Malformation (SHFM) is a complex congenital anomaly characterized by highly variable presentations affecting the hands and/or feet.
• Existing classifications for SHFM and syndactyly may not adequately encompass all observed phenotypes, particularly those with overlapping features or less typical presentations.

Purpose of the Study:

• To identify and characterize a subset of patients with SHFM presenting with "mitten hand" syndactyly.
• To review and evaluate current classification systems for split hand and syndactyly in light of challenging clinical presentations.
• To propose improvements for classification schemes to better include diverse phenotypes and aid clinical management.

Main Methods:

• Clinical epidemiologic study of the Manitoba population to identify patients with SHFM.
• Literature review to identify additional cases with similar presentations.
• Analysis of clinical and radiographic findings for classification challenges.

Main Results:

• A subset of patients with SHFM presented with "mitten hand" syndactyly, with deficiencies often unrecognized before imaging.
• Observed osseous fusions and disorganization complicated classification efforts.
• Many patients exhibited overlapping findings across different subtypes within existing classification systems.

Conclusions:

• The identified cohort presents a classification challenge for SHFM and syndactyly, impacting genetic counseling.
• Current general classifications may overlook critical phenotypic details.
• Effective classification requires integration of clinical and radiographic findings to assist clinicians in managing distal limb anomalies.