Prolonged thrombocytopenia in a child with severe neonatal alloimmune reaction and Noonan syndrome

Abstract

Fetomaternal alloimmune thrombocytopenia (FMAIT) caused by maternal antibodies is the leading cause of severe neonatal thrombocytopenia. A 1-month-old Caucasian girl was referred to our Hematology Clinic for persistent thrombocytopenia diagnosed after a bleeding episode. Diagnostic tests suggested FMAIT. Mild thrombocytopenia persisted for 18 months, and subsequent findings of dysmorphic facies, short stature and mild pulmonary stenosis led to the hypothesis of Noonan syndrome (NS), which was confirmed by genetic test. Other hematological abnormalities were excluded and she had no further bleeding episodes. This case illustrates the possibility of different diagnoses with the same clinical manifestations. The persistence of thrombocytopenia longer than expected associated with typical physical features led to the diagnosis of NS.

Prolonged thrombocytopenia in a neonate with Noonan syndrome: a case report

“…12 In patients with PTPN11-associated NS accompanied by thrombocytopenia, the reported mutation sites include c.218C>T and c.181G>A, both of which are in exon 3. 8,16 However, in our case, the mutation site was c.1517A>C, which is located in exon 13, and bone marrow cytology did not show dyshematopoiesis. Additionally, our proband had a good prognosis of recovered platelet levels, which could not be explained by JMML.…”

“…In one term PTPN11 gene mutation-positive neonate with NS, thrombocytopenia was definitively induced by a fetomaternal alloimmune reaction. 8 We report here a term and macrosomic neonate with NS and a PTPN11 gene mutation. In this neonate, there was prolonged, but fluctuating, thrombocytopenia.…”

“…In one term PTPN11 gene mutation-positive neonate with NS, thrombocytopenia was definitively induced by a fetomaternal alloimmune reaction. 8 …”

Refractory thrombocytopenia could be a rare initial presentation of Noonan syndrome in newborn infants: a case report and literature review

“…This study hypothesized that bleeding diatheses in NS may be associated with metabolic disturbances or interaction of cell surface signals [ 18 ]. An one-month old child with prolonged thrombocytopenia was diagnosed as Noonan syndrome in a short communication by Salva [ 19 ]. Mutation in the PTPN11 gene was found in the case.,Another case with mutation of T73I in PTPN11 gene was also presented with prolonged thrombocytopenia [ 20 ].…”

Genetic conditions of short stature: A review of three classic examples

“…Disordered bleeding has been reported in patients with NS and can range from mild (easy bruising, menorrhagia) to severe (significant bleeding during surgical procedures) (1,8). Several coagulation factor deficiencies (typically factors VIII, XI, or XII), platelet dysfunction, and thrombocytopenia have been described in individuals with NS (1,16,(52)(53)(54). About 50% of individuals with NS have abnormalities in the intrinsic coagulation pathway and 65% display abnormal bruising or bleeding tendencies (2).…”