Rapid detection by hydrops panel of Noonan syndrome with PTPN11 mutation (p.Thr73Ile) and persistent thrombocytopenia

Abstract

Abstract Background Nonimmune hydrops fetalis (NIHF) is still a challenging diagnosis. The differential diagnosis is extensive and the success of identifying a cause depends on the thoroughness of efforts to establish a diagnosis. For the early diagnosis of NIHF, a virtual gene panel diagnostic tool was developed. The female premature baby in question was delivered via emergency cesarean at 30 + 1 weeks of gestational age (GA) due to rapidly developing NIHF to a healthy mother. The family history was noncontributory. Methods DNA of the family was extracted and sequenced by the virtual hydrops panel with whole‐exome sequencing. Results The hydrops panel revealed Noonan syndrome (NS) with a germline mutation in PTPN11 c.218C>T (p.Thr73Ile). Conclusion The diagnosis of our patient was rapidly confirmed by the hydrops panel. The variant of c.218C>T (p.Thr73Ile) has not yet been described in literature relating to NIHF. Only a few case reports of this variant are known. This particular mutation is associated with Noonan syndrome, congenital heart defect and persistent thrombocytopenia. Few reveal juvenile myelomonocytic leukemia.

Keywords

• hydrops panel
• next‐generation sequencing
• nonimmune hydrops fetalis
• Noonan syndrome
• rare variant