Prenatal ultrasound signs of Aarskog‐Scott syndrome in a twin pregnancy: A case report

We describe the case of Aarskog‐Scott syndrome in a twin pregnancy with the prenatal finding of shortened fetal long bones.


Aarskog-Scott syndrome, genetic diagnosis, prenatal diagnosis, twin pregnancy
Aarskog-Scott syndrome is a rare X-linked developmental disorder (that could phenotypically overlap with other syndromes) characterized by a variety of structural anomalies that involve mainly the face, distal extremities, and external genitalia. 1Aarskog-related signs include short-statured individuals with craniofacial anomalies such as hypertelorism, short nose, ptosis, and genital dysmorphism such as shawl scrotum and cryptorchidism. 2 describe below the case of a dichorionic-diamniotic twin pregnancy obtained by an in vitro fertilization procedure (intracytoplasmic sperm injection plus embryo transfer) with the prenatal finding of shortened fetal long bones.Aarskog-Scott syndrome was diagnosed at birth.The patient in the case was a 33-year-old Caucasian woman, gravida 1, para 0. The patient and her husband were heterozygote carriers for cystic fibrosis.Genetic counseling was provided to the couple.The pregnancy was achieved after intracytoplasmic sperm injection plus embryo transfer for severe oligo-astheno-teratozoospermia.A 5AA blastocyst was transferred.The patient's personal and family histories were unremarkable.At 7 +1 weeks of pregnancy two gestational chambers, two yolk sacs, and two embryos with cardiac activity were found, with crown-rump lengths of 11 and 10 mm, respectively.The fetal DNA test (11 +6 weeks) showed low risk; it was performed at the couple's request.The nuchal translucency was 2.50 mm (above the 95th centile) for both fetuses and was performed at 11 +0 weeks of pregnancy.The morphologic ultrasound (16 +2 and 21 weeks) was found to be normal.The early ultrasound was performed at the request of the couple, the other was the fetal anatomy scan of the second trimester.
An invasive prenatal diagnosis for cystic fibrosis mutations was offered but the couple declined.At 26 +1 weeks of pregnancy, biometry of the femur and humerus was reported to be on the 5th centile for both fetuses, following the growth curves (Figure 1).At 30 +2 weeks of pregnancy the third-trimester scan was normal, but the femoral length was below the 3rd centile (Figure 2).
It was explained to the couple that long bone biometrics could indicate skeletal abnormalities in the third trimester if growth stopped.
Fetal biometry at 34 +6 weeks reported that the femur lengths and head circumferences were below the 5th centile, which followed the curves.A neonatology consultation was also performed.
At 37 +0 weeks of pregnancy the femur lengths were below the 3rd centile but head and abdominal circumferences were normal (Figure 3).The couple was told that further diagnostic tests would need to be performed in the postnatal period.At 37 +4 weeks, the patient was admitted to our unit with maternal hypertension, low platelets, and proteinuria.This was preeclampsia with HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome.
The patient had signed the consent for vaginal birth; the office ultrasound had seen both fetuses in the cephalic position.The 24-h proteinuria was found to be 347 mg.At 37 +6 weeks, medical induction of labor was started using vaginal and oral prostaglandins.Oxytocin was started as soon as dilatation was 6 cm.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.© 2024 The Authors.International Journal of Gynecology & Obstetrics published by John Wiley & Sons Ltd on behalf of International Federation of Gynecology and Obstetrics.The second fetus was delivered 7 min after the birth of the first by vacuum extraction due to fetal bradycardia with Apgar scores of 5 and 9 at 1 and 5 min, respectively.Birth weight was 2500 g (5th centile), length was 47 cm (10th centile), and head circumference was 31 cm (1st centile).Both siblings presented peculiar dysmorphic features (Figure 4), and direct sequencing of the FGD1 gene confirmed the diagnosis.The novel variant (found in the mother) FGD1 c.1327 C>T (Arg442Cys) was found in both siblings, confirming the diagnosis.Multiple ligation-dependent probe amplification FGD1 analysis excluded duplication or deletion of the gene.The siblings were followed up and at 6 months of age presented a typical Aarskog-Scott dysmorphic sign, normal neurodevelopment F I G U R E 1 (a) Femoral length at 26 +1 weeks of gestation of fetus 1.(b) Femoral length at 26 +1 weeks of gestation of fetus 2 on the 5th centile.

F I G U R E 3
Femoral length curves of (a) fetus 1 and (b) fetus 2.