Detection of a de novo Y278C mutation in FGFR3 in a pregnancy with severe fetal hypochondroplasia: Prenatal diagnosis and literature review

ObjectiveWe describe a prenatal molecular diagnosis of hypochondroplasia (HCH) in a pregnancy not at risk of HCH and review the literature on prenatal diagnosis of HCH.Case reportA 28-year-old primigravid woman was referred for genetic counseling at 30 weeks of gestation because of short-limbed dwarfism in the fetus. The woman had a body height of 152 cm. Her husband had a body height of 180 cm. Level II ultrasound showed a normal amount of amniotic fluid and a singleton fetus with fetal biometry equivalent to 30 weeks except for short limbs. Fetal biometry measurements were as follows: biparietal diameter = 7.38 cm (30 weeks); head circumference = 28.14 cm (30 weeks); abdominal circumference (AC) = 24.64 cm (30 weeks); femur length (FL) = 3.97 cm ( 0.18); humerus = 3.64 cm ( G, TAC > TGC transversion in exon 7 leading to a p.Tyr278Cys (Y278C) mutation in the FGFR3 protein. aCGH analysis revealed no genomic imbalance in cord blood. After delivery, the fetus had short limbs, a narrow thorax, brachydactyly, and relative macrocephaly. Cytogenetic analysis of cultured placental cells revealed a karyotype of 46,XX.ConclusionPrenatal diagnosis of abnormal ultrasound findings suspicious of ACH should include a differential diagnosis of HCH by molecular analysis of FGFR3.