American Journal of Medical Genetics 138A:278–281 (2005)

Clinical ReportNovel Phenotype of Craniosynostosis and OcularAnterior Chamber Dysgenesis With a FibroblastGrowth Factor Receptor 2 MutationEmma McCann,1* Stephen B. Kaye,2 William Newman,3 Gail Norbury,4 Graeme C.M. Black,5,6 and Ian H. Ellis1

1Department of Clinical Genetics, Royal Liverpool Children’s Hospital, Eaton Rd, Liverpool, United Kingdom2St. Paul’s Eye Unit, 8Z Link, Royal Liverpool University Hospital, Prescot Street, Liverpool, United Kingdom3Department of Paediatric Ophthalmology, Royal Liverpool Children’s Hospital, Eaton Rd, Liverpool, United Kingdom4Regional Molecular Genetics Laboratory, Level 5, Camelia Botnar Laboratories, Great Ormond Street Hospital for Children, London,United Kingdom5Academic Unit of Medical Genetics and Regional Genetic Service, St. Mary’s Hospital, Manchester, United Kingdom6Manchester Royal Eye Hospital, Central Manchester and Manchester Children’s University Hospitals NHS Trust, Oxford Road,Manchester, United Kingdom

Fibroblast growth factor receptor 2 (FGFR2)mutations are associated with syndromic andnon-syndromic craniosynostoses. More recentlyit has been recognized that FGFR2 may have a rolein the development of the anterior chamber of theeye following the finding of a specific FGFR2mutation (p.Ser351Cys, c.1231 C!G) with an-terior chamber dysgenesis. Affected patients hada severe craniofacial phenotype and clinicalcourse. A child with a different FGFR2 muta-tion (p.Ala344Ala, c1032 G!A heterozygote), pre-mature fusion of the sagittal suture, and anAxenfeld–Rieger anomaly but otherwise normalclinical course is reported. The case providesfurther evidence that FGFR2 has a role in anteriorchamber embryogenesis. � 2005 Wiley-Liss, Inc.

KEY WORDS: FGFR2; craniosynostosis; scapho-cephaly; anterior chamber dys-genesis; Axenfeld–Rieger

INTRODUCTION

Fibroblast growth factor receptor 2 (FGFR2) is a member ofthe high affinity, tyrosine kinase protein family that bindsfibroblast growth factors.Mutations in this gene are associatedwith craniosynostosis syndromes including Crouzon, Pfeiffer,Apert, and Jackson–Weiss [Jabs et al., 1994; Reardon et al.,1994; Lajeunie et al., 1995]. Unclassifiable craniosynostosishas also been observed with FGFR2 mutations [Steinbergeret al., 1996].

Axenfeld–Rieger malformation refers to a collection ofocular findings including anomalies of the anterior chamberangle and aqueous drainage structures that are associatedwith a high risk of glaucoma as well as iris hypoplasia,corectopia, and posterior embryotoxon. It may be associated

with extraocular developmental abnormalities of the umbi-licus, dentition, heart, or limbs. A number of genes areimplicated in the development of the Axenfeld–Rieger anom-aly and are reviewed by Lines et al. [2002].

Okajima et al. [1999] previously reported on three caseswithanterior chamber dysgenesis, craniosynostosis, and with aFGFR2 mutation. A further case is presented with differentanterior chamber findings, sagittal suture craniosynostosis,and in whom a FGFR2 mutation was detected.

CLINICAL REPORT

A boy, the second child of unrelated parents, was found tohave a right-sided cataract at 3 weeks of age that requiredsurgical extraction at 5 weeks of age. Additional anterior seg-ment developmental abnormalities suggestive of Axenfeld–Rieger anomaly were also present including right-sidedmicrocornea, bilateral posterior embryotoxon, and bilateraliris hypoplasia with corectopia. At the time of diagnosis, andsubsequently intraocular pressures were normal. Posteriorsegment examination also revealed no abnormalities. Therewere no umbilical, teeth, limb or heart abnormalities.

Scaphocephaly was detected at 6 months of age (Fig. 1a,b)and a skull X-ray confirmed premature fusion of the sagittalsuture. Magnetic resonance imaging of his brain revealed anArnold–Chiari malformation with prolapse of the cerebel-lar tonsils 5 mm below the level of the foramen magnum.Surgical correction of his craniosynostosis was necessarybecause of concerns about raised intracranial pressure. Therewere no other dysmorphic features and development was ageappropriate.

At 6 years of age, the patient remains under regularophthalmology and craniofacial follow-up; there are no newproblems and no learning difficulties. The patient’s karyotypeis normal.

Ophthalmologic examination of the mother revealed mildiris hypoplasia and bilateral embryotoxon. She also hasmild exophthalmus but no craniosynostosis. The patient’sfather and older sibling have no abnormal eye findings onclinical examination. Thematernal grandmotherwas reportedby the family to have developed glaucoma around 55 yearsof age.

MUTATION ANALYSIS

AG!A base change at c.1032 in exon 10 of the FGFR2 genewas detected by Aci 1 restriction enzyme digestion of amplified

*Correspondence to: Emma McCann, Royal Liverpool Chil-dren’s Hospital, Eaton Rd., Liverpool, L12 2AP, United Kingdom.E-mail: emma.mccann@rlc.nhs.uk

Received 5 May 2005; Accepted 27 June 2005

DOI 10.1002/ajmg.a.30944

� 2005 Wiley-Liss, Inc.

genomic DNA (Fig. 2) and confirmed by sequence analysis(Fig. 3a,b). This change of nucleotide is reported to create anewdonor splice site resulting in a 51 base pair deletion andshortening of the distance between the disulphide bond in theImmunoglobulin-like IIIc domain and transmembrane domain[Li et al., 1995].

The p.Ser351Cys (c.1231 C!G) mutation was excluded.Mutations were sought in other relevant genes (FOXC1,PITX2, and PITX3) but none were found.

The mother has been found to be heterozygous for the samemutation by sequence analysis. It has not been possible to testother family members at this time.

Fig. 1. a: Facial appearance and (b) side profile of proband illustrating scaphocephaly (postsurgery).

Fig. 2. PCR digest with Aci 1 restriction enzyme.Lane 1: 50 bp ladder; (lane 2) uncut PCR product 221 bp size; (lanes 3 and 9) normal controls showingfragment sizes of 90, 80, and 51 bp; (lanes 4, 5, 6, and 8) the proband’s c.1032G!Aheterozygousmutation showing fragment sizes of 170 and 51 bp; (lane 7)negative control.

Anterior Chamber Defects, Craniostenosis, and FGFR2 279

DISCUSSION

Crouzon syndrome is thepredominant phenotype inpatientswith a c.1032 G!A (p.Ala344Ala) FGFR2 mutation [Jabset al., 1994; Reardon et al., 1994; Del Gatto and Breathnach,1995; Li et al., 1995; Ma et al., 1995; Park et al., 1995].Steinberger et al. [1996] also described a large Turkish familywith this mutation—the phenotypic spectrum was wide andincluded one case with synostosis of the sagittal and lambdoid

sutures. There was no anterior chamber involvement butseveral cases had hypertelorism, exophthalmus, astigmatism,myopia, and strabismus. In the family described, both affectedmembers had eye involvement, the probandwasmore severelyaffected and in addition had sagittal suture synostosis.

Severe ocular anterior chamberdysgenesis (Peters anomaly)has previously been described in three patients with severecraniosynostosis syndromes [Okajima et al., 1999]. The ocularfindings in those patients included Peters anomaly in two andopaque corneae, thickened irides, and ciliary bodies, andshallow anterior chambers with occluded angles in the third.In all three cases, the same FGFR2 mutation (p. Ser351Cysc.1231 C!G) was detected. In the family described here, theanterior segment abnormalities were considerablymilder and,in the proband included microcornea, congenital cataract, andiris hypoplasia associated with corectopia. Intrafamilialvariability in the abnormalities between the proband and hismother, who had mild signs of anterior segment dysgenesis,wasnoted. In particular therewasno corneal opacification as ischaracteristic of Peters anomaly.

It is well recognized that anterior segment dysgenesisphenotypes (including Peters anomaly, Axenfeld anomaly,Rieger anomaly, iris hypoplasia) form a spectrum of abnorm-alities [Perveen et al., 2000]. A number of reports havedescribed a range of phenotypes within the same individual[Doward et al., 1999] or family [Holmstrom et al., 1991].Furthermore a high degree of phenotypic variability in theanterior segment abnormalities is recognized in associationwith allelic mutations in PITX2 [Alward et al., 1998; Perveenet al., 2000], PITX3 [Semina et al., 1998; Addison et al., 2005],and PAX6 [Hanson et al., 1994; Mirzayans et al., 1995].Therefore we suggest that anterior ocular developmentalabnormalities may be associated with FGFR2 mutations andthat the phenotypic spectrum may also be broad. This issupported by other reports in the literature with variableanterior chamber abnormalities in association with craniosy-nostosis syndromes (Table I) but in which no mutation datawere available [van Dyke et al., 1983; Traboulsi and Maume-nee, 1992; Jones et al., 1993].

The functional consequence of the p.Ala344Ala, c1032G!Amutation described is uncertain. While it has been demon-strated to result in a small in-frame deletion, it is not knownwhether this is functionally null and also whether the effectson splicing are partial or complete [Li et al., 1995]. CertainlyFGF signaling is known to be critical in the signaling betweenthe lens and ocular mesenchyme [Lovicu and Overbeek,1998], and since FGFRs 1–3 are all expressed in the develop-ing lens [de Iongh et al., 1997; Huang et al., 2003] it is perhapsnot surprising that mutations in FGFR2 may result incataractogenesis.

The patient described further supports a role for FGFR2 inthe development of the anterior chamber of the eye. It is anappropriate gene to consider for mutation analysis in indivi-duals with anterior chamber abnormalities and craniosynos-tosis. Accordingly, a formal ophthalmological assessment

Fig. 3. a and b: Sequence analysis of the FGFR2 gene showing a G to Aheterozygous change at c.1032 G!A.

TABLE I. Clinical Features, Eye Involvement, and Mutation Status

Craniofacialfeatures Eye involvement Mutation

Current case Scaphocephaly Axenfeld–Rieger anomaly Ala344AlaOkajima et al. [1999] 1 Pfeiffer Peters Ser351Cys

2 Crouzon Peters Ser351Cys3 Crouzon See text Ser351Cys

Jones et al. [1993] Pfeiffer Coloboma (atypical) UnknownVan Dyke et al. [1983] Pfeiffer Corectopia UnknownTraboulsi andMaumenee [1992]

Pfeiffer Peters Unknown

280 McCann et al.

should be offered to those patients in whom FGFR2mutationsare detected in order to anticipate potential problems.

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