Prenatal ultrasonographic and molecular diagnosis of Apert syndrome

Rapid detection of de novo P253R mutation in FGFR2 using uncultured amniocytes in a pregnancy affected by polyhydramnios, Blake's pouch cyst, and Apert syndrome

OBJECTIVE

To present prenatal ultrasound and molecular genetic diagnosis of Apert syndrome.

CASE REPORT

A 30-year-old, gravida 3, para 2 woman was referred for genetic counseling at 32 weeks of gestation because of polyhydramnios and craniofacial and digital abnormalities in the fetus. She had undergone amniocentesis at 18 weeks of gestation because of maternal anxiety. Results of amniocentesis revealed a karyotype of 46,XX. A prenatal ultrasound at 32 weeks of gestation revealed a female fetus with a fetal biometry equivalent to 32 weeks, polyhydramnios with an increased amniotic fluid index of 26.1 cm, frontal bossing, midface hypoplasia, hypertelorism, Blake's pouch cyst with an apparent posterior fossa cyst in communication with the fourth ventricle on axial images, digital fusion, and bilateral syndactyly of the hands and feet. A DNA testing for the FGFR2 gene was immediately performed using uncultured amniocytes obtained by repeated amniocentesis, which revealed a heterozygous c.758C>G, CCT>CGT transversion leading to a p.Pro253Arg (P253R) mutation in the FGFR2 gene. Subsequently, a diagnosis of Apert syndrome was made. Molecular analysis of the FGFR2 gene in the parents did not reveal such a mutation. The fetus postnatally manifested frontal bossing, midface hypoplasia, and bilateral syndactyly of the hands (mitten hands) and feet.

CONCLUSION

Prenatal diagnosis of polyhydramnios, frontal bossing, and midface hypoplasia associated with brain and digital abnormalities should include a differential diagnosis of Apert syndrome. A molecular analysis of FGFR2 using uncultured amniocytes is useful for rapid confirmation of Apert syndrome at prenatal diagnosis.

Acrocephalosyndactyly, Apert type, in a newborn: Cerebral sonography

We describe the clinical and cerebral ultrasonographic features of a rare case of type 1 acrocephalosyndactyly (Apert syndrome). The patient was a newborn male whose twin had died in utero. Most cases of Apert syndrome are sporadic, although autosomal dominant inheritance has also been reported. Diagnosis is based on physical examination together with imaging data. Since Apert syndrome can give rise to numerous CNS abnormalities, affected newborns should undergo echoencephalography for more complete characterization of their malformations.

Diagnosis of Apert syndrome in the second-trimester using 2D and 3D ultrasound

OBJECTIVES

To illustrate how Apert syndrome, a rare autosomal dominant genetic syndrome, can be detected in the second-trimester of pregnancy using 2D ultrasound, and how 3D ultrasound examination may provide parents with a better understanding of the structural defects affecting their baby.

METHODS

Fetal Medicine Unit database searches to identify Apert syndrome cases.

RESULTS

Five cases of Apert syndrome were suspected in the second-trimester when sonography showed abnormal extremities including syndactyly, and an abnormal skull shape. In 1 case there was increased nuchal translucency with a normal fetal karyotype in the first-trimester. In all cases, a mutation of the FGFR2 gene confirmed the diagnosis of Apert syndrome. 3D ultrasound was used to show parents the extent of the abnormalities of the skull, face and extremities. Parents were counseled by craniofacial surgeons and geneticists.

CONCLUSION

Apert syndrome can be accurately suspected in the second-trimester by careful ultrasound examination of the fetus including the extremities and skull shape. 3D ultrasound can be a useful adjunct to 2D examination for parental counseling.

Apert syndrome: what prenatal radiographic findings should prompt its consideration?

Apert syndrome was diagnosed in a newborn with typical facial and digital features whose only detected prenatal abnormality had been agenesis of the corpus callosum. This prompted a review of the central nervous system findings in all cases of Apert syndrome treated at the Craniofacial Center Boston Children's Hospital between 1978 and 2004. Two of 30 patients with Apert syndrome had prenatal identification of mild dilatation of the lateral cerebral ventricles and complete agenesis of the corpus callosum (ACC) documented with both ultrasound and MRI. Both had the common S252W mutation of FGFR2. Though cranial and orbital malformations typical of Apert were eventually seen in these fetuses in the third-trimester, even in retrospect, these were not detectable at mid second-trimester, ultrasound screening for congenital malformations. Hand malformations also went undetected in the second-trimester despite extensive imaging by experienced radiologists. We conclude that prenatal ultrasonographic identification of mild ventriculomegaly or ACC should stimulate a careful search for features of Apert syndrome and prompt follow-up imaging to look for bony abnormalities that have later onset. Prenatal molecular testing for Apert mutations should be considered in cases of mild ventriculomegaly and ACC.

MR imaging of fetal head and neck anomalies

This article describes an approach to imaging of fetal head and neck anomalies. Topics include cleft lip and palate, facial clefts, amniotic band sequence, micrognathia and retrognathia, ocular and orbital abnormalities, craniosynostosis, posterior nuchal translucency, cephaloceles, vascular anomalies, and tumors. Some of the more common syndromes are also described.

Congenital abnormalities of the musculoskeletal system: Perinatal evaluation and long-term outcome

Many musculoskeletal malformations can be detected by prenatal US. Whether isolated or part of a syndrome, these anomalies can have a significant impact on the entire life of the individual. Nonfatal conditions may be subtle and become more recognizable in the second and third trimester. After delivery, radiography helps confirm the diagnosis. US, CT, and MRI all have a role in imaging the primary abnormality, the follow-up effects of treatment, and in monitoring for potential complications that may develop over time. Three-dimensional imaging has an increasing role, in US, CT, and MRI, both in the prenatal and postnatal periods.

Prenatal ultrasound diagnosis of fetal craniosynostosis

OBJECTIVE

Craniosynostosis is defined as the premature closure of the calvarial sutures. The prevalence of this heterogeneous condition is 1 in 2000 and approximately 100 different forms have been described with an established genetic transmission in half of them. Prenatal diagnosis of craniosynostosis relies mainly on identification of associated anomalies and molecular analysis of fetal DNA, which is only feasible in some syndromic forms and in well-documented families. The objective of this study was to investigate the value of prenatal ultrasound examination of cranial sutures in fetuses at risk for craniosynostosis.

METHODS

Forty fetuses at risk for craniosynostosis on the basis of either a family history (Group 1, n = 16) or skull deformity suspected on a first-level fetal ultrasound examination (Group 2, n = 24) were retrospectively investigated. Craniosynostosis was suspected on the basis of skull deformities when present, however the diagnosis was only made in cases where there was a loss of hypoechogenicity of the normal sutures. All infants had both clinical and radiological investigations performed postnatally.

RESULTS

In Group 1, serial ultrasound examination from 12 weeks' gestation onwards led to accurate prenatal diagnosis in all 16 cases. Dysmorphism and skull deformity preceded closure of the sutures by 4 to 16 weeks. In Group 2, prenatal diagnosis was correct in 23/24 cases. There were no false-negative results in either group.

CONCLUSIONS

This series questions further the uncertain genetic determinism of craniosynostosis and seems to rule out the hypothesis of a deformation sequence following primary closure of the cranial sutures. It also suggests that ultrasound examination is useful to demonstrate closure of the sutures in the third trimester of pregnancy in most affected cases.

Prenatal diagnosis of Apert syndrome: report of two cases

Two de novo cases with Apert Syndrome detected prenatally are presented herein. In the first, fetal ultrasound findings of syndactyly of the hands, craniosynostosis and proptosis resulted in a prenatal diagnosis in the nineteenth week of gestation. This is the earliest prenatal diagnosis of this syndrome in a not-at-risk case. Following counseling, this pregnancy was terminated and subsequent pathological examination and DNA analysis confirmed the diagnosis of Apert Syndrome and coarctation of the aorta. In the second case, fetal ultrasound at 21 weeks' gestation revealed a hypoplastic left heart and clover-leaf skull. Following counseling, this pregnancy was also terminated. Further examination of the fetus and DNA analysis led to a diagnosis of Apert Syndrome. These cases emphasize the need to complete a thorough fetal ultrasound in cases with potentially lethal cardiac abnormality and the importance of incorporating a fetal pathologist, as well as a medical geneticist, in the investigations performed after delivery or pregnancy termination when a fetal abnormality is detected on ultrasound.

Ultrasound diagnosis of craniosynostosis

OBJECTIVE

To retrospectively study prenatal ultrasound images of patients with craniosynostosis to determine the extent to which prenatal diagnosis is possible.

METHOD

Prenatal ultrasound images of 19 patients with postnatally diagnosed metopic or coronal suture craniosynostosis were retrospectively reviewed. The 26 ultrasound examinations obtained were compared with normal images and tables of gestation.

RESULTS

It was not possible to diagnose craniosynostosis in the first trimester. In the second trimester, Kleeblattschädel was diagnosed at 20.5 weeks. A multilobular shape to the skull and diastasis of the frontotemporal suture was identified. In a second child with Kleeblattschädel, the cephalic index was above normal 86.4 (normal range 70 to 86), and the head circumference to abdominal circumference was increased. In the third trimester, the head shape deformation was more obvious. Brachycephaly diagnosis was made in the second trimester. In Crouzon syndrome the hypertelorism was identified at 19.9 weeks. Plagiocephaly was diagnosed at 21.4 weeks. In trigonocephaly the reduced cephalic index was noted at 18.8 weeks. In the third trimester, the deformity was diagnosed in all cases.

CONCLUSION

No diagnosis of craniosynostosis was made in the first trimester. In the second trimester, it was possible to diagnose Kleeblattschädel, trigonocephaly, brachycephaly (bilateral coronal suture craniosynostosis), and plagiocephaly (unilateral coronal suture craniosynostosis) in nine of the examinations. In the third trimester and at term, it was possible to diagnose previously listed conditions from six of the seven examinations obtained. Kleeblattschädel was suspected during original examination. A total of 15 examinations of 26 were correctly diagnosed during this investigation.

Prenatal diagnosis of sporadic Apert syndrome: a sequential diagnostic approach combining three-dimensional computed tomography and molecular biology

Apert syndrome is characterized by coronal craniosynostosis, midfacial hypoplasia, symmetrical syndactyly of the hands and feet described as 'mitten-like' with varying degrees of mental retardation. It results from a mutation of the fibroblast growth factor-2 (FGFR2) gene. In the absence of a family history, prenatal diagnosis may be difficult based on sonography alone. We report a case in which the prenatal diagnosis of Apert syndrome was suspected by ultrasonography, established by three-dimensional computed tomography scan (3DTS) and confirmed by the detection of a mutation on amniotic cells. This underscores the usefulness of a sequential diagnostic approach combining 3DTS and molecular biology in cases in which sonography alone is not con- clusive.

Contribution of tridimensional sonography and magnetic resonance imaging to prenatal diagnosis of Apert syndrome at mid-trimester

A diagnosis of Apert syndrome, suspected at 24 weeks' gestation after conventional sonography showing turribrachycephaly and syndactyly of hands and feet, was confirmed at 26 weeks' gestation by tridimensional sonography and magnetic resonance imaging. This is only the second prenatal diagnosis reported at mid-trimester, excluding cases published from affected mothers or in connection with a context of recurrence. Additional findings have been collected from tridimensional sonography (mid-facial hypoplasia, downslanting palpebral fissures) and from magnetic resonance imaging (verticalization of the clivus and flattened angle of the cranial base).