Prenatal diagnosis of triphalangeal thumb-polysyndactyly syndrome by ultrasonography combined with genetic testing:A case report

BACKGROUND Triphalangeal thumb-polysyndactyly syndrome(TPT-PS)is a rare type of congenital limb deformity,and most studies focus on the genetics.Case reports of the sonographic characteristics of TPT-PS during pregnancy are rare.CASE SUMMARY A 30-year-old woman(G3P1)who had pregnancies with TPT-PS fetuses is presented.The possibility of TPT-PS was shown by ultrasound performed at the 19th wk of pregnancy,featuring hands with six metacarpals,an extra digit at the 5th finger side,and an abnormally widened thumb.Whole-exome sequencing was subsequently conducted.The results showed that exons 1-17 of the LMBR1 gene had a heterozygous duplication,with a length of approximately 253 kb.CONCLUSION We suggest prenatal ultrasound examination combined with genetic testing to diagnose TPT-PS accurately and to help clinicians and patients make decisions.