Apert Syndrome Workup
- Author: Harold Chen, MD, MS, FAAP, FACMG; Chief Editor: Bruce Buehler, MD more...
Laboratory Studies
- Molecular analysis of Apert syndrome
- The molecular mechanism is exquisitely specific with a narrow mutational spectrum.
- More than 98% of cases are caused by specific missense substitution mutations, involving adjacent amino acids (Ser252Trp, Ser252Phe, or Pro253Arg) in exon 7 of FGFR2.
- The remaining cases are due to Alu-element insertion mutations in or near exon 9.
Imaging Studies
- Skull radiography
- Skull radiography can be performed to evaluate for craniostenosis, which usually involves coronal sutures and maxillary hypoplasia.
- Abnormalities include sclerosis of suture line, bony bridging and beaking along the suture line, an indistinct suture line, turribrachycephaly, shallow orbits, and hypoplastic maxillae.
- Spinal radiography
- Spinal fusions, most commonly at the levels of C3-4 and C5-6, appear to be progressive and occur at the site of subtle congenital anomalies. They may not be apparent as congenital features.
- Small-sized vertebral body and reduced intervertebral disc space are indicators of subsequent bony fusion.
- Limb radiography: Radiographs of the limbs depict multiple epiphyseal dysplasia, short humeri, and glenoid dysplasia.
- Hand radiography
- Radiography of the hands can be performed to evaluate for cutaneous and osseous syndactyly.
- The characteristic finding is complete syndactyly involving the second and fifth digits (mitten hands).
- Multiple progressive synostosis involves distal phalanges, proximal fourth and fifth metacarpals, capitate, and hamate.
- Symphalangism of interphalangeal joints is progressive.
- Radiography of the distal phalanx reveals shortened and radial deviation.
- Radiography of the proximal phalanx of the thumbs reveals delta-shaped deformity.
- Foot radiography
- Radiography of the feet can be performed to evaluate for cutaneous and osseous syndactyly. The characteristic finding is complete syndactyly involving the second and fifth digits (sock feet).
- Fusion of tarsal bones, metatarsophalangeal and interphalangeal joints, and adjacent metatarsals
- Delta-shaped proximal phalanx of the first toes
- Occasional partial or complete duplication of the proximal phalanx of the great toes and first metatarsals
- CT scanning
- CT with comparative 3-dimensional reconstruction analysis of the calvaria and cranial bases has become the most useful radiological examination in identifying skull shape and presence or absence of involved sutures.
- CT can precisely reveal the pathological anatomy and permit specific operative planning.
- MRI
- MRI reveals the anatomy of the soft-tissue structures and associated brain abnormalities (ie, nonprogressive ventriculomegaly; hydrocephalus; complete or partial absence of the septum pellucidum; absence of septal leaflets; and thinning, deficiency, or agenesis of the corpus callosum).[17, 18]
- MRI can also reveal spatial arrangement of the bones.
Other Tests
- Psychometric evaluation
- Hearing assessment
Genetic counseling [19]
A negligible risk for Apert syndrome is noted in siblings of affected individuals when parents are not affected, except in the case of germinal mosaicism; in this case, the risk in future siblings depends on the proportion of germ cells that bear the mutant allele.[20]
A 50% risk for Apert syndrome is present in the siblings of an affected individual if a parent is also affected.
A 50% risk for Apert syndrome is observed in offspring of an affected individual.
Advanced paternal age effect in new mutations has been shown clinically and demonstrated conclusively at the molecular level.
Prenatal diagnosis [19]
Despite the striking physical features seen in newborns with Apert syndrome, de novo cases are often not diagnosed prenatally, or are only identified in the third-trimester.[17, 18]
Prenatal ultrasonographic diagnosis can be made based on findings of acrocephaly, mittenlike hands, and proximally placed and radially deviated thumbs.[21] CNS malformations such as mild ventriculomegaly and agenesis of corpus callosum may be visible in some fetuses with Apert syndrome before the pathognomonic skeletal changes are revealed. The abnormal cranial shape and orbital hypertelorism may be absent or very subtle in the second trimester of pregnancy, becoming obvious only in the third trimester. However, Apert syndrome can be accurately suspected in the second trimester by careful ultrasonographic examination of the fetus, including the extremities and skull shape using 3-dimensional ultrasonography.
Use of 3-dimensional ultrasonography to demonstrate the fetal abnormalities (eg, premature closure of the coronal suture; a wide metopic suture; abnormalities of the hands, feet, and face) is particularly useful in parental counseling.[22]
If the molecular defect has been identified in the affected parent, prenatal molecular diagnosis can be achieved by direct DNA testing on fetal DNA obtained from amniocentesis or chronic villus sampling (CVS). In general, linkage analysis can be considered if a mutation has not been detected in the affected parent (although >98% of patients with Apert syndrome tested so far have FGFR2 mutations) and at least 2 affected relatives are available.
The abnormal sonographic findings with a high suspicion of Apert syndrome should be confirmed by detection of a mutation in the FGFR2 gene. Two mutations, S252W C→G and P253R C→G are found in 98% of patients.[23]
Fetoscopy to visualize fetal anomalies comparable to Apert syndrome in a pregnancy at risk is an invasive procedure and is not currently used.
Noninvasive prenatal diagnosis of Apert syndrome using polymerase chain reaction (PCR) and restriction enzyme digestion of cffDNA in maternal plasma has been reported.[24] Au et al have developed a real-time qPCR assay using molecular beacon probes to detect the S252W mutation in the FGFR2 gene, in fetal DNA extracted from plasma of pregnant women at risk for Apert syndrome.[25]
Lajeunie E, Cameron R, El Ghouzzi V, de Parseval N, Journeau P, Gonzales M. Clinical variability in patients with Apert's syndrome. J Neurosurg. Mar 1999;90(3):443-7. [Medline].
Khong JJ, Anderson PJ, Hammerton M, et al. Differential effects of FGFR2 mutation in ophthalmic findings in Apert syndrome. J Craniofac Surg. Jan 2007;18(1):39-42. [Medline].
Khong JJ, Anderson P, Gray TL, et al. Ophthalmic findings in apert syndrome prior to craniofacial surgery. Am J Ophthalmol. Aug 2006;142(2):328-30. [Medline].
Khong JJ, Anderson PJ, Hammerton M, Roscioli T, Selva D, David DJ. Differential effects of FGFR2 mutation in ophthalmic findings in Apert syndrome. J Craniofac Surg. Jan 2007;18(1):39-42. [Medline].
Cohen MM Jr, Kreiborg S, Lammer EJ, Cordero JF, Mastroiacovo P, Erickson JD. Birth prevalence study of the Apert syndrome. Am J Med Genet. Mar 1 1992;42(5):655-9. [Medline].
Cohen MM Jr, Kreiborg S. An updated pediatric perspective on the Apert syndrome. Am J Dis Child. Sep 1993;147(9):989-93. [Medline].
Cohen MM Jr, Kreiborg S, Lammer EJ, Cordero JF, et al. Birth prevalence study of the Apert syndrome. Am J Med Genet. Mar 1 1992;42(5):655-9. [Medline].
Glaser RL, Broman KW, Schulman RL, Eskenazi B, Wyrobek AJ, Jabs EW. The paternal-age effect in Apert syndrome is due, in part, to the increased frequency of mutations in sperm. Am J Hum Genet. Oct 2003;73(4):939-47. [Medline].
Goriely A, McVean GA, Rojmyr M, Ingemarsson B, Wilkie AO. Evidence for selective advantage of pathogenic FGFR2 mutations in the male germ line. Science. Aug 1 2003;301(5633):643-6. [Medline].
Jabs EW, Li X, Scott AF, Meyers G, Chen W, Eccles M. Jackson-Weiss and Crouzon syndromes are allelic with mutations in fibroblast growth factor receptor 2. Nat Genet. Nov 1994;8(3):275-9. [Medline].
Muenke M, Schell U, Hehr A, Robin NH, Losken HW, Schinzel A. A common mutation in the fibroblast growth factor receptor 1 gene in Pfeiffer syndrome. Nat Genet. Nov 1994;8(3):269-74. [Medline].
Reardon W, Winter RM, Rutland P, Pulleyn LJ, Jones BM, Malcolm S. Mutations in the fibroblast growth factor receptor 2 gene cause Crouzon syndrome. Nat Genet. Sep 1994;8(1):98-103. [Medline].
Rutland P, Pulleyn LJ, Reardon W, Baraitser M, Hayward R, Jones B. Identical mutations in the FGFR2 gene cause both Pfeiffer and Crouzon syndrome phenotypes. Nat Genet. Feb 1995;9(2):173-6. [Medline].
Wilkie AO, Slaney SF, Oldridge M, Poole MD, et al. Apert syndrome results from localized mutations of FGFR2 and is allelic with Crouzon syndrome. Nat Genet. Feb 1995;9(2):165-72. [Medline].
Przylepa KA, Paznekas W, Zhang M, Golabi M, Bias W, Bamshad MJ, et al. Fibroblast growth factor receptor 2 mutations in Beare-Stevenson cutis gyrata syndrome. Nat Genet. 1996;13:492-494.
Yu K, Herr AB, Waksman G, Ornitz DM. Loss of fibroblast growth factor receptor 2 ligand-binding specificity in Apert syndrome. Proc Natl Acad Sci USA. 2000;97:14536-14541.
Quintero-Rivera F, Robson CD, Reiss RE, et al. Apert syndrome: what prenatal radiographic findings should prompt its consideration?. Prenat Diagn. Oct 2006;26(10):966-72. [Medline].
Quintero-Rivera F, Robson CD, Reiss RE, et al. Intracranial anomalies detected by imaging studies in 30 patients with Apert syndrome. Am J Med Genet A. Jun 15 2006;140(12):1337-8. [Medline].
Chen H. Apert syndrome. In: Atlas of Genetic Diagnosis and Counseling. Totowa, New Jersey: Humana Press; 2006:61-69.
Allanson JE. Germinal mosaicism in Apert syndrome. Clin Genet. May 1986;29(5):429-33. [Medline].
Athanasiadis AP, Zafrakas M, Polychronou P, Florentin-Arar L, Papasozomenou P, Norbury G. Apert syndrome: the current role of prenatal ultrasound and genetic analysis in diagnosis and counselling. Fetal Diagn Ther. 2008;24(4):495-8. [Medline].
David AL, Turnbull C, Scott R, et al. Diagnosis of Apert syndrome in the second-trimester using 2D and 3D ultrasound. Prenat Diagn. Jul 2007;27(7):629-32. [Medline].
Oldridge M, Zackai EH, McDonald-McGinn DM, Iseki S, et al. De novo alu-element insertions in FGFR2 identify a distinct pathological basis for Apert syndrome. Am J Hum Genet. Feb 1999;64(2):446-61. [Medline].
Raymond FL, Whittaker J, Jenkins L, Lench N, Chitty LS. Molecular prenatal diagnosis: the impact of modern technologies. Prenat Diagn. Jul 2010;30(7):674-81. [Medline].
Au PK, Kwok YK, Leung KY, Tang LY, Tang MH, Lau ET. Detection of the S252W mutation in fibroblast growth factor receptor 2 (FGFR2) in fetal DNA from maternal plasma in a pregnancy affected by Apert syndrome. Prenat Diagn. Feb 2011;31(2):218-20. [Medline].
[Guideline] Cunniff C. Prenatal screening and diagnosis for pediatricians. Pediatrics. Sep 2004;114(3):889-94. [Medline].
Apert M. De l'acrocephalosyndactylie. Bull Mém Soc Med Hop Paris. 1906;23:1310-1313.
Blank CE. Apert's syndrome (a type of acrocephalosyndactyly). Observations on a British series of thirty-nine cases. Ann Hum Genet. 1960;24:151-64.
Chang CC, Tsai FJ, Tsai HD, et al. Prenatal diagnosis of Apert syndrome. Prenat Diagn. 1998;18:621-5.
Cohen MM Jr. Craniosynostoses: phenotypic/molecular correlations. Am J Med Genet. Apr 10 1995;56(3):334-9. [Medline].
Cohen MM Jr. Craniosynostosis update 1987. Am J Med Genet Suppl. 1988;4:99-148. [Medline].
Cohen MM Jr, ed. Craniosynostosis: Diagnosis, evaluation, and management. New York, NY: Raven Press; 1986.
Cohen MM Jr, Kreiborg S. Cutaneous manifestations of Apert syndrome. Am J Med Genet. Jul 31 1995;58(1):94-6. [Medline].
Cohen MM Jr, Kreiborg S. Hands and feet in the Apert syndrome. Am J Med Genet. May 22 1995;57(1):82-96. [Medline].
Cohen MM Jr, Kreiborg S. Skeletal abnormalities in the Apert syndrome. Am J Med Genet. Oct 1 1993;47(5):624-32. [Medline].
Cohen MM Jr, Kreiborg S. The central nervous system in the Apert syndrome. Am J Med Genet. Jan 1990;35(1):36-45. [Medline].
Cohen MM Jr, Kreiborg S. Visceral anomalies in the Apert syndrome. Am J Med Genet. Mar 15 1993;45(6):758-60. [Medline].
Cuerda E, del Pozo J, Rodriguez-Lozano J, Pena-Penabad C, Fonseca E. Acne in Apert's syndrome: treatment with isotretinoin. J Dermatolog Treat. Jan 2003;14(1):43-5. [Medline].
Cunningham ML, Seto ML, Ratisoontorn C, Heike CL, Hing AV. Syndromic craniosynostosis: from history to hydrogen bonds. Orthod Craniofac Res. May 2007;10(2):67-81. [Medline].
DeGiovanni CV, Jong C, Woollons A. What syndrome is this? Apert syndrome. Pediatr Dermatol. Mar-Apr 2007;24(2):186-8. [Medline].
Do Amaral CMR, Di Domizio G, Buzzo CL. Surgical treatment of Apert syndrome and Crouzon anomaly by gradual bone distraction. Plast Reconstr Surg. Sept 2009;124(3).
Erickson JD, Cohen MM Jr. A study of parental age effects on the occurrence of fresh mutations for the Apert syndrome. Ann Hum Genet. Jul 1974;38(1):89-96. [Medline].
Freiman A, Tessler O, Barankin B. Apert syndrome. Int J Dermatol. Nov 2006;45(11):1341-3. [Medline].
Hansen WF, Rijhsinghani A, Grant S, Yankowitz J. Prenatal diagnosis of Apert syndrome. Fetal Diagn Ther. Mar-Apr 2004;19(2):127-30. [Medline].
Hohoff A, Joos U, Meyer U, Ehmer U, Stamm T. The spectrum of Apert syndrome: phenotype, particularities in orthodontic treatment, and characteristics of orthognathic surgery. Head Face Med. 2007;3:10. [Medline]. [Full Text].
Kan SH, Elanko N, Johnson D, et al. Genomic screening of fibroblast growth-factor receptor 2 reveals a wide spectrum of mutations in patients with syndromic craniosynostosis. Am J Hum Genet. Feb 2002;70(2):472-86. [Medline]. [Full Text].
Kaplan L. Clinical assessment and multispeciality management of Apert syndrome. Clin Plast Surg. 1991;18:217-225.
Kreiborg S, Cohen MM Jr. Characteristics of the infant Apert skull and its subsequent development. J Craniofac Genet Dev Biol. 1990;10(4):399-410. [Medline].
Leonard CO, Daikotu NH, Winn K. Prenatal fetoscopic diagnosis of the Apert syndrome. Am J Med Genet. 1982;11:5-9.
Liptak GS, Serletti JM. Pediatric approach to craniosynostosis. Pediatr Rev. Oct 1998;19(10):352; quiz 359. [Medline].
Lomri A, Lemonnier J, Hott M, de Parseval N, et al. Increased calvaria cell differentiation and bone matrix formation induced by fibroblast growth factor receptor 2 mutations in Apert syndrome. J Clin Invest. Mar 15 1998;101(6):1310-7. [Medline].
Mahieu-Caputo D, Sonigo P, Amiel J, Simon I, Aubry MC, Lemerrer M. Prenatal diagnosis of sporadic Apert syndrome: a sequential diagnostic approach combining three-dimensional computed tomography and molecular biology. Fetal Diagn Ther. Jan-Feb 2001;16(1):10-2. [Medline].
Moloney DM, Slaney SF, Oldridge M, Wall SA, et al. Exclusive paternal origin of new mutations in Apert syndrome. Nat Genet. May 1996;13(1):48-53. [Medline].
Narayan H, Scott IV. Prenatal ultrasound diagnosisof Apert's syndrome. Prenat Diagn. 1991;10:187-192.
Park WJ, Theda C, Maestri NE, Meyers GA, et al. Analysis of phenotypic features and FGFR2 mutations in Apert syndrome. Am J Hum Genet. Aug 1995;57(2):321-8. [Medline].
Rajenderkumar D, Bamiou D, Sirimanna T. Management of hearing loss in Apert syndrome. J Laryngol Otol. May 2005;119(5):385-90. [Medline].
Renier D, Arnaud E, Cinalli G, Sebag G, Zerah M, Marchac D. Prognosis for mental function in Apert's syndrome. J Neurosurg. Jul 1996;85(1):66-72. [Medline].
Slaney SF, Oldridge M, Hurst JA, et al. Differential effects of FGFR2 mutations on syndactyly and cleft palate in Apert syndrome. Am J Hum Genet. May 1996;58(5):923-32. [Medline].
Tay T, Martin F, Rowe N, et al. Prevalence and causes of visual impairment in craniosynostotic syndromes. Clin Experiment Ophthalmol. Jul 2006;34(5):434-40. [Medline].
Thompson DN, Slaney SF, Hall CM, Shaw D, et al. Congenital cervical spinal fusion: a study in Apert syndrome. Pediatr Neurosurg. Jul 1996;25(1):20-7. [Medline].
Tolarova MM, Harris JA, Ordway DE, Vargervik K. Birth prevalence, mutationrate, sex ratio, parents' age, and ethnicity in Apert syndrome. Am J Med Genet. 1997;72:394-398.
Verma S, Draznin M. Apert syndrome. Dermatol Online J. 2005;11:15-18. [Medline].
von Gernet S, Golla A, Ehrenfels Y, Schuffenhauer S, Fairley JD. Genotype-phenotype analysis in Apert syndrome suggests opposite effects of the two recurrent mutations on syndactyly and outcome of craniofacial surgery. Clin Genet. 2000;57:137-139.

