OBSOLETE: Acrocephalosyndactyly

Acrocephalosyndactyly (ACS) is an obsolete umbrella term that was historically used to describe a group of rare congenital malformation syndromes characterized by the combination of acrocephaly (a pointed or tower-shaped skull due to premature fusion of cranial sutures, also known as craniosynostosis) and syndactyly (fusion or webbing of the fingers and/or toes). This term encompassed several distinct genetic conditions that are now classified separately, including Apert syndrome (ACS type I), Saethre-Chotzen syndrome (ACS type III), Pfeiffer syndrome (ACS type V), and other related craniosynostosis syndromes. Because these conditions have been individually characterized with distinct genetic etiologies, the grouped designation of acrocephalosyndactyly is no longer in active clinical use and is considered obsolete in current nosology. The conditions formerly grouped under this term primarily affect the skeletal system, particularly the craniofacial bones and the extremities. Premature fusion of one or more cranial sutures leads to abnormal skull shape and can result in increased intracranial pressure, which may affect brain development and vision if untreated. Syndactyly ranges from mild cutaneous webbing to complex bony fusion of digits. Additional features may include midface hypoplasia, hypertelorism, and intellectual disability of variable severity depending on the specific syndrome. Treatment for the individual conditions within this former grouping typically involves multidisciplinary surgical management, including staged craniofacial surgery to release fused sutures and reconstruct the skull, hand surgery to separate fused digits, and supportive therapies such as speech therapy and developmental support. Genetic counseling is recommended for affected families, as most of the individual syndromes follow autosomal dominant inheritance patterns, often involving mutations in fibroblast growth factor receptor (FGFR) genes or TWIST1.

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