Summary Card
Overview
Apert syndrome (acrocephalosyndactyly) is a rare genetic condition marked by characteristic differences in the skull, face, hands, and feet. It has a distinctive presentation affecting the upper limbs.
Clinical Features
Key features are craniosynostosis, midface hypoplasia, and complex syndactyly affecting both the hands and feet. Upper limb anomalies significantly impact function.
Management
The Upton classification guides the surgical management of Apert's hand. The primary goal is to optimize function and create a five-digit structure while preserving neurovascular integrity.
Primary Contributor: Dr Suzanne Thomson, Educational Fellow.
Reviewer: Dr Kurt Lee Chircop, Educational Fellow.
Overview of Apert's Hand
Key Point
Apert syndrome (acrocephalosyndactyly) is a rare genetic condition marked by characteristic differences in the skull, face, hands, and feet. It involves severe syndactyly and craniosynostosis, with a distinctive presentation affecting the upper limbs.
Apert syndrome (acrocephalosyndactyly) is a rare genetic condition marked by characteristic differences in the skull, face, hands, and feet. It involves severe syndactyly and craniosynostosis, with a distinctive presentation affecting the upper limbs.
Apert syndrome is characterized by:
- Bicoronal craniosynostosis: Premature fusion of the coronal sutures in the skull.
- Midface hypoplasia: Underdevelopment of the middle facial structures.
- Severe, complex syndactyly of the hands and feet: Fusion of the digits leading to mitten-like hands and feet, often requiring staged surgical corrections.
The image below illustrates an Apert's hand.
Epidemiology
The estimated prevalence is 15.5 per 1,000,000, making it a relatively rare condition. Apert syndrome accounts for about 4.2% of all craniosynostosis cases (Cohen Jr., 1992).
Aetiology
Apert syndrome results from a mutation in the fibroblast growth factor receptor 2 (FGFR2) gene, located on chromosome 10. The condition follows an autosomal dominant inheritance pattern, although most cases are de novo mutations. FGFR2 mutations cause altered signaling during early embryonic development, leading to characteristic physical anomalies.
Related Syndromes
- Crouzon syndrome: Craniosynostosis without hand anomalies.
- Jackson-Weiss syndrome: Craniosynostosis, 2nd and 3rd digit syndactyly, broad proximal phalanx, fused metatarsals and tarsals.
- Pfeiffer syndrome: Craniosynostosis, broad and deviated great toes and thumbs.
- Antley-Bixler syndrome: Craniosynostosis, slender hands, PIPJ contractures.
😎
Fun Fact:
The eponymous name is derived from the French paediatrician Eugene Apert, who described the condition in 1906.
The eponymous name is derived from the French paediatrician Eugene Apert, who described the condition in 1906.
Clinical Features of Apert's Hand
Key Point
Key features are craniosynostosis, midface hypoplasia, and complex syndactyly affecting both the hands and feet. Upper limb anomalies significantly impact function, particularly in the shoulder, elbow, and hand.
Key features are craniosynostosis, midface hypoplasia, and complex syndactyly affecting both the hands and feet. Upper limb anomalies significantly impact function, particularly in the shoulder, elbow, and hand.
Key Features
- Craniosynostosis
- Midface hypoplasia
- Complex syndactyly of the hands and feet
Upper Limb Manifestations
- Shoulder: Asymmetrical development of the glenohumeral joint, with a hypoplastic glenoid fossa leading to restricted shoulder movement, which worsens with growth.
- Elbow: Radiocapitellar articulation anomalies that limit elbow function.
Hand Anomalies
The hand deformities in Apert syndrome can be classified based on the extent and type of syndactyly:
- Complete vs. Incomplete Syndactyly: Syndactyly that either extends to the tips of the digits (complete) or does not (incomplete).
- Simple vs. Complex Syndactyly: Syndactyly involving only soft tissue (simple) or both soft tissue and bones (complex).
Specific Finger Involvement
- The index, long, and ring fingers typically present with complex syndactyly.
- Simple syndactyly is often observed between the ring and little fingers.
Functional Impact
- The degree of first webspace syndactyly, along with radial clinodactyly of the thumb (a curvature of the thumb), is critical in determining hand function. The severity of these deformities has the most significant impact on fine motor skills and grasping ability.
Upton classification of Apert's hand is illustrated in the table below.
The image below illustrates clinical features of Apert's hand according to its types.
Management of Apert's Hand
Key Point
The Upton classification guides the surgical management of Apert's hand. The primary goal is to optimize function and create a hand that resembles a five-digit structure while preserving neurovascular integrity.
The Upton classification guides the surgical management of Apert's hand. The primary goal is to optimize function and create a hand that resembles a five-digit structure while preserving neurovascular integrity.
Investigations
- X-rays of the hands to assess bony abnormalities.
- Anaesthetic workup to ensure surgical safety, usually around 4 months of age.
- Genetic testing if the diagnosis is not established, to confirm a unifying diagnosis.
Management Goals
- Optimize hand function while preserving neurovascular bundles.
- Achieve an aesthetic outcome as close as possible to a five-digit hand.
- Surgery is staged, with the first procedures starting at around 4 months to ensure anaesthetic safety, usually performed before craniofacial surgery.
Surgical Staging
This is based on Upton classification.
Upton Type 1 Hand
- At 4 months: Release of the 2nd and 4th webspaces with skin grafting.
- Craniofacial surgery may follow.
- 6 years: Further surgery includes deepening of the webspace and thumb lengthening using an opening wedge osteotomy of the delta phalanx, potentially with K-wire fixation.
- Incisions are made in straight lines, with advancement of v-shaped dorsal and volar flaps that interdigitate at the webspace.
- A dorsal approach is used to protect neurovascular bundles, with internal neurolysis to facilitate digital separation.
- Bony connections are divided using a 15 blade or osteotome.
- Skin grafts are harvested considering future hair growth patterns.
Upton Type 2 Hand
- First stage (4 months): Release of the 2nd and 4th webspaces.
- Second stage: Release of the 1st and 3rd webspaces with release of the tight adductor pollicis fascia.
- Thumb lengthening is achieved with an opening wedge osteotomy for the radially deviated thumb.
Upton Type 3 Hand
- First stage: Release of the 1st and 4th webspaces to free the border digits.
- Second stage: Release the 2nd or 3rd webspaces, depending on the phalangeal fusion pattern. A five-digit hand may not always be the surgical goal.
- Release of the tight adductor pollicis fascia, thumb lengthening, and opening wedge osteotomy for thumb deviation. Bone grafts may be necessary for thumb lengthening.
😎
Fun Fact:
Children with Apert syndrome often have hyperhidrosis, so avoiding surgery during warmer seasons may reduce maceration and improve graft success.
Children with Apert syndrome often have hyperhidrosis, so avoiding surgery during warmer seasons may reduce maceration and improve graft success.
Conclusion
Upon completing this article, you will have accomplished the following:
1. Apert Syndrome Overview: Apert syndrome is a rare genetic disorder caused by mutations in the FGFR2 gene, leading to craniosynostosis, midface hypoplasia, and severe syndactyly of the hands and feet. It occurs in about 15.5 per million and follows an autosomal dominant inheritance.
2. Clinical Features: Key characteristics include craniosynostosis, midface hypoplasia, and complex syndactyly. Upper limb deformities impact shoulder, elbow, and hand function, with syndactyly affecting fine motor skills and grasp.
3. Investigations: X-rays assess bony deformities, and genetic testing confirms the diagnosis. An anaesthetic workup is done before surgery, typically starting around 4 months of age.
4. Surgical Management: The Upton classification guides staged surgeries to separate webspaces and correct thumb deformities. Early procedures focus on releasing the 2nd and 4th webspaces, with later surgeries addressing thumb length and webspace deepening.
1. Apert Syndrome Overview: Apert syndrome is a rare genetic disorder caused by mutations in the FGFR2 gene, leading to craniosynostosis, midface hypoplasia, and severe syndactyly of the hands and feet. It occurs in about 15.5 per million and follows an autosomal dominant inheritance.
2. Clinical Features: Key characteristics include craniosynostosis, midface hypoplasia, and complex syndactyly. Upper limb deformities impact shoulder, elbow, and hand function, with syndactyly affecting fine motor skills and grasp.
3. Investigations: X-rays assess bony deformities, and genetic testing confirms the diagnosis. An anaesthetic workup is done before surgery, typically starting around 4 months of age.
4. Surgical Management: The Upton classification guides staged surgeries to separate webspaces and correct thumb deformities. Early procedures focus on releasing the 2nd and 4th webspaces, with later surgeries addressing thumb length and webspace deepening.
Further Reading
- Cohen MM Jr, Kreiborg S, Lammer EJ, Cordero JF, Mastroiacovo P, Erickson JD, Roeper P, MartÃnez-FrÃas ML. Birth prevalence study of the Apert syndrome. Am J Med Genet. 1992 Mar 1;42(5):655-9. doi: 10.1002/ajmg.1320420505. PMID: 1303629.
- Kracoff SL. Radiographic Characteristics of the Hand in Apert Syndrome. J Hand Surg Asian Pac Vol. 2020 Mar;25(1):82-86. doi: 10.1142/S2424835520500113. PMID: 32000596.
- Al-Qattan MM. A Review of the Genetics and Pathogenesis of Syndactyly in Humans and Experimental Animals: A 3-Step Pathway of Pathogenesis. Biomed Res Int. 2019 Sep 15;2019:9652649. doi: 10.1155/2019/9652649. PMID: 31637260; PMCID: PMC6766129.
- Upton J. Apert syndrome. Classification and pathologic anatomy of limb anomalies. Clin Plast Surg. 1991 Apr;18(2):321-55. PMID: 2065493.
- Zucker RM, Cleland HJ, Haswell T. Syndactyly correction of the hand in Apert syndrome. Clin Plast Surg. 1991 Apr;18(2):357-64. PMID: 1648464.
- Stauffer A, Farr S. Is the Apert foot an overlooked aspect of this rare genetic disease? Clinical findings and treatment options for foot deformities in Apert syndrome. BMC Musculoskelet Disord. 2020 Nov 28;21(1):788. doi: 10.1186/s12891-020-03812-2. PMID: 33248465; PMCID: PMC7700708.
- Harvey I, Brown S, Ayres O, Proudman T. The Apert hand--angiographic planning of a single-stage, 5-digit release for all classes of deformity. J Hand Surg Am. 2012 Jan;37(1):152-8. doi: 10.1016/j.jhsa.2011.10.017. PMID: 22196295.
- Raposo-Amaral CE, Denadai R, Furlan P, Raposo-Amaral CA. Treatment of Apert Hand Syndrome: Strategies for Achieving a Five-Digit Hand. Plast Reconstr Surg. 2018 Oct;142(4):972-982. doi: 10.1097/PRS.0000000000004815. PMID: 29994846.
