Acromelic frontonasal dysplasia

Acromelic frontonasal dysplasia (AFND) is an extremely rare congenital malformation syndrome characterized by the combination of frontonasal dysplasia (abnormal development of the front of the face and nose) and limb anomalies, particularly affecting the hands and feet (acromelic involvement). The condition is present at birth and affects multiple body systems, most prominently the craniofacial structures and the skeletal system. Key craniofacial features include widely spaced eyes (hypertelorism), a broad or bifid nasal tip, median cleft of the nose or upper lip, and sometimes central nervous system anomalies such as agenesis of the corpus callosum or encephalocele. Limb abnormalities typically include preaxial polydactyly (extra digits on the thumb or big toe side), brachydactyly (short fingers or toes), and tibial hypoplasia or aplasia. At least two genetic subtypes have been described. Acromelic frontonasal dysplasia type 1 (AFND1) is caused by pathogenic variants in the ZSWIM6 gene, while type 2 (AFND2) has been linked to variants in the NBAS gene. Both forms follow an autosomal recessive inheritance pattern. Intellectual disability of variable severity may be present in some affected individuals. Additional features can include cryptorchidism, brain malformations, and talipes equinovarus (clubfoot). There is currently no cure or disease-specific treatment for acromelic frontonasal dysplasia. Management is supportive and symptomatic, typically involving a multidisciplinary team including craniofacial surgeons, orthopedic specialists, neurologists, and developmental specialists. Surgical correction of craniofacial and limb anomalies may be undertaken depending on severity. Early developmental intervention and educational support are recommended for individuals with intellectual disability. Genetic counseling is important for affected families to understand recurrence risks.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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