Crouzon Syndrome: Visual Diagnosis

Clinical assessment and FGFR2 mutation analysis in a Chinese family with Crouzon syndrome: A case report

RATIONALE

Crouzon syndrome is an autosomal dominant genetic disorder caused by mutations in fibroblast growth factor receptor 2 (FGFR2) and one of the most common types of craniosynostosis. Here we report the detection of FGFR2 mutation and its related clinical findings in 2 patients with Crouzon syndrome from a Chinese family.

PATIENT CONCERNS

We report a case of a 28-year-old male patient presented with the chief complaint of gradually blurring of his eyes over the last 6 months before visiting our clinics. History revealed low visual acuity in his right eye since childhood. Physical examination showed that both the patient and his mother have the appearance of craniofacial dysostosis, mandibular prognathism, ocular proptosis, short superior lip, scoliosis, and thoracic deformity.

DIAGNOSIS

Auxiliary examinations lead to the diagnosis of Crouzon syndrome with binocular optic atrophy, myelinated retina nerve fibers, and ametropia in both eyes, and amblyopia in the right eye of the male patient. The molecular genetic analysis confirmed the diagnosis by detecting a heterozygous pathogenic mutation c.1026C > G (C342W) in exon 10 of FGFR2 in both the patient and his mother, but not in any of the unaffected family members.

INTERVENTIONS AND OUTCOMES

None.

LESSONS

Our study confirms the presence of optic nerve atrophy in patients with Crouzon syndrome carrying FGFR2 C342W mutations and indicates that MRI and funduscopy should be performed to examine the optic nerve changes for patients with Crouzon syndrome.

Detection of G338R FGFR2 mutation in a Vietnamese patient with Crouzon syndrome

Crouzon syndrome is a rare autosomal dominant genetic disorder, which causes the premature fusion of the cranial suture. Fibroblast growth factor receptor 2 (FGFR2) mutations are well-known causatives of Crouzon syndrome. The current study aimed to assess the FGFR2 gene associated with Crouzon syndrome in a Vietnamese family of three generations and to characterize their associated clinical features. The family included in the present study underwent complete clinical examination. A patient was clinically examined and presented with typical features of Crouzon syndrome including craniosynostosis, shallow orbits, ocular proptosis and midface hypoplasia. However the patient had normal hands and feet, a normal hearing ability and normal intelligence. Genomic DNA collected from all family members (except from a 16 week-old-foetus) and 200 unrelated control subjects from the same population was extracted from leukocytes obtained from peripheral blood samples. Genomic DNA was extracted from the 16-week-old foetus via the amniotic fluid of the mother. All coding sequences of FGFR2 were amplified via polymerase chain reaction and directly sequenced. A heterozygous FGFR2 missense mutation (c.1012G>C, p.G338R) in exon 10 was identified in the patient with Crouzon but not in other family members, the 16 week-old-foetus or the controls. This mutation was therefore determined to be the causative agent of Crouzon syndrome. In addition, a novel heterozygous silent mutation (c.1164C>T, p.I388I) in exon 11 of the FGFR2 gene was identified in the patient with Crouzon, his mother and the 16-week-old fetus, but not in other family members. The mutation in exon 10 of FGRF2 was confirmed via restriction-enzyme digestion. The gain of the BsoBI site confirmed the FGFR2 mutation in exon 10 of the patient with Crouzon. This molecular finding may provide useful information to aid clinicians in the diagnosis of Crouzon syndrome and may also aid early prenatal diagnoses.

C278F mutation in FGFR2 gene causes two different types of syndromic craniosynostosis in two Chinese patients

The current study was performed with aim to investigate the fibroblast growth factor receptor 2 (FGFR2) gene in two Chinese families with two different forms of syndromic craniosynostosis, and to characterize their associated clinical features. Two families underwent complete ophthalmic examinations, and two patients from each family were diagnosed with craniosynostosis. Genomic DNA was extracted from leukocytes of peripheral blood collected from these two families and from 200 unrelated subjects within the same population as controls. Exons 8 and 10 of the FGFR2 gene were amplified by polymerase chain reaction and directly sequenced. Ophthalmic examinations of the two patients revealed shallow orbits and ocular proptosis, accompanied by midface hypoplasia and craniosynostosis. Case 1 had retinal detachment, abnormal limbs and hands, while case 2 exhibited normal hands and feet upon clinical examination. A heterozygous FGFR2 missense mutation c.833G>T (C278F) in exon 8 was identified in these two patients, but not in unaffected family members or the normal controls. Although FGFR2 gene mutations and polymorphisms have been studied in various ethnic groups, we report a mutation of FGFR2 in two different Chinese patients with two different types of syndromic craniosynostosis.

FGFR2 mutations and associated clinical observations in two Chinese patients with Crouzon syndrome

The aim of the present study was to identify mutations in the fibroblast growth factor receptor 2 (FGFR2) gene in patients with Crouzon syndrome and characterize the associated clinical features. A total of two Chinese patients diagnosed with Crouzon syndrome underwent complete examinations, including best-corrected visual acuity, slit-lamp, examination, fundus examination, optical coherence tomography and computed tomography of the skull. Genomic DNA was extracted from peripheral blood samples collected from the patients, as well as their family members and 200 unrelated control subjects from the same population. Exons 8 and 10 in the FGFR2 gene were amplified by polymerase chain reaction and directly sequenced. Patient #1 had a heterozygous missense mutation (c.1025G>A, p.C342Y) in exon 10 of FGFR2. Patient #2 had a heterozygous mutation (c.1084+1 G>T; IVS10+1G>T) in intron 10. The mutations were not present in any of the unaffected family members or unrelated control subjects. These findings expand the mutation spectrum of FGFR2, and are valuable for genetic counseling in addition to prenatal diagnosis in patients with Crouzon syndrome.