Prenatal Diagnosis of Antley-Bixler Syndrome and POR Deficiency

BACKGROUND Prenatal diagnosis of severe bone diseases is challenging and requires complete and precise analysis of fetal anomalies to guide genetic investigation and parental counselling. CASE REPORT We report a rare case of Antley-Bixler syndrome prenatally diagnosed at 26 weeks' gestation by ultrasound and computed tomography in a 28-year-old woman with a history of early termination of pregnancy for "malposition of the inferior limbs". The prenatal ultrasound scan showed severe femoral bowing and frontal bossing. Taking into account the high probability of a recurrent severe skeletal disorder, a computed tomography (CT) scan was proposed. CT findings revealed bilateral femora deformation, craniosynostosis, severe midface hypoplasia, and radiohumeral synostosis. These anomalies strongly suggested Antley-Bixler syndrome. Sequencing of the POR gene in the fetus and the parents revealed compound heterozygous mutations in exon 9 and intron 7, both inherited from each parent, and this finding allowed genetic counseling. CONCLUSIONS The first step in the proper prenatal diagnosis of fetal bone disorders is the precise analysis of ultrasonographic images. However, when a severe fetal inherited disorder is strongly suspected in late mid-trimester, CT may be discussed and usefully contribute to diagnosis and prognosis assessment.