Shortened fetal long bones: A notable intrauterine phenotypic feature in SHOX-associated skeletal dysplasia.

OBJECTIVE

To explore the intrauterine phenotypic spectrum of short stature homeobox-containing (SHOX) gene-associated skeletal dysplasia and provide genetic counseling at-risk pregnancies.

METHOD

We analyzed the fetuses with SHOX-microdeletions identified by single nucleotide polymorphism (SNP)-array. The intrauterine phenotypes and outcomes were further elaborated.

RESULTS

Nine fetuses carrying a single SHOX-microdeletion were reported, with deletion sizes ranging from 0.134 to 1.35 Mb. Shortened long bones were observed in all fetuses, varying from -2.0 standard deviation (SD) to -5.3 SD. Moreover, all cases had a femur length/foot ratio less than 0.87 and a femur/abdominal circumference ratio greater than 0.16, suggesting that non-lethal skeletal dysplasia may be involved. Two fetuses showed intrauterine growth restriction, and two had nasal bone hypoplasia. Prenatal ultrasonography did not reveal other obvious anomalies, including the Madelung deformity. Five microdeletions were inherited and one was de novo. Five terminations and four newborns were recorded. Two newborns had normal stature, and two were short-statured (height <3rd percentile), with one having inflexible wrists.

CONCLUSIONS

SHOX haploinsufficiency may manifest with shortened fetal long bones. The combination of history taking, prenatal ultrasonography, and SNP-array can prompt early prenatal diagnosis and timely postnatal treatment of SHOX-associated skeletal dysplasia.