A 24-year-old, gravida 2 para 1 patient presented to our center at 28 weeks’ gestation. Second-trimester anatomy ultrasonography showed a singleton fetus with absent radii (Fig 1), micrognathia, malrotation of hands, and shortened humeri and ulnae.An extensive genetic history was obtained on consultation with the genetics team. A complete 4-generation pedigree was performed: the patient was in a nonconsanguineous relationship and had a healthy sibling without physical anomalies. The paternal family history was remarkable for multiple members with anatomic anomalies, including an infant (the paternal uncle) born with an absent scapula, malformed arms, and a cleft palate who died during the neonatal period. There was also a maternal second-degree cousin with a history of severe arm anomalies including bilateral absent forearms. The pregnant patient opted for genetic amniocentesis. An expanded chromosome microarray analysis (CMA) was ordered by the maternal-fetal medicine team. CMA results showed a loss of chromosome 1q21.1 of about 0.405 MB, which encompasses the loss of RBM8A, a gene associated with thrombocytopenia-absent radius (TAR) syndrome. Subsequently, this chromosome loss was also noted in the paternal CMA, and maternal testing showed a pathogenic hemizygous variant in the RBM8A gene. Additional imaging at 30 weeks’ gestation identified a small amount of asymmetry at the caudothalamic groove (Fig 2).There appears to be a lack of strong evidence on the optimal management approach for patients with TAR syndrome. Therefore, our team began this patient’s care with a multidisciplinary care conference to discuss the appropriate management. A multidisciplinary care meeting with the maternal-fetal medicine, fetal intervention, transfusion medicine, pediatric hematology, neonatology and medical genetics teams was held. The aim was to ensure that all the prenatal, delivery, and postnatal management was appropriately anticipated. Once it was determined which specialties would be necessary for the patient’s care, we arranged for the family to meet with the specialty teams throughout the prenatal period. We expected that by engaging the family in the decision-making, the family’s anxiety about the anticipated clinical care could be decreased.Whether cordocentesis to assess the platelet count in the fetus would be beneficial was comprehensively discussed. The incentive was to potentially transfuse platelets if the fetus was found to have severe thrombocytopenia (platelet count <50 × 103/µL [<50 × 109/L]). The decision was made to avoid the procedure because of a lack of evidence of benefit and the inherent risk of bleeding with this invasive procedure. (1)(2)(3)(4) In place of cordocentesis, serial fetal growth ultrasonography and neurosonography studies (to rule out intracranial hemorrhage) were implemented every 3 to 4 weeks to ensure appropriate interval growth and rule out hemorrhage of fetal organs.Delivery at 37 to 38 weeks’ gestation was deemed appropriate to allow coordination of care with multiple specialties and minimize the risk of hemorrhage. Neonatology, maternal-fetal medicine, pediatric transfusion medicine, and hematology would be represented in the operating room, along with a laboratory technician. The use of forceps or vacuum during delivery was to be avoided as it was deemed to increase the risk of fetal intracranial hemorrhage. An elective cesarean section might diminish the risk of intracranial hemorrhage and allow a coordinated delivery with all the relevant disciplines involved.The team discussed with the family that a “point-of-care” complete blood cell count (CBC) analyzer would be available in the operating room on the day of delivery to measure the cord platelet and red blood cell counts. In addition, platelet and red blood cell units would be readily available. We believed that this approach would shorten the time to platelet transfusion, if needed. Predelivery appointments allowed the family to discuss the risk and implications of thrombocytopenia. It was also explained that the infant would likely be dependent on platelet transfusions initially but with time, platelet counts would be expected to improve through infancy and childhood.A female infant was delivered atraumatically in cephalic presentation at 37 weeks’ gestation in a scheduled cesarean section. The infant emerged active and well appearing; she required intermittent blow-by oxygen for the first 10 minutes after birth but then did well in room air. Her Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. No bleeding, petechiae, or purpura were noted at birth. She had a birthweight of 2,995 g (27th percentile), a body length of 49 cm (47th percentile), and occipitofrontal diameter of 34 cm (54th percentile). The infant was also noted to have shortened forearms with slight flexion at the elbows and wrists (Fig 3).A cord blood sample was obtained and analyzed by the point-of-care CBC analyzer in the operating room, which showed hemoglobin of 11.9 g/dL (119 g/L) and platelet count of 14 × 103/µL (14 × 109/L) platelets. The hematology team recommended a 5-mL/kg transfusion of platelets, which was administered in the delivery room via a central catheter through the umbilical vein. A red blood cell transfusion was administered on the first day after birth per the hematology team recommendations. The infant was admitted to the NICU, where the anatomic anomalies were confirmed on radiography (Fig 4). Based on hematology team recommendations, platelets were transfused to maintain a platelet count greater than 75 × 109/µL (75 × 109/L).A grade III/VI systolic murmur was appreciated on the left lower sternal border, and echocardiography findings were found to be unremarkable. On the second day after birth, feedings were started, and the infant received a 10 mL/kg transfusion in the setting of a platelet count of 61 × 103/µL (61 × 109/L). The platelet count was noted to appropriately respond, with a post-transfusion increase to 168 × 103/µL (168 × 109/L). Head ultrasonography on the third day after birth showed subtle asymmetry at the caudothalamic groove, which was read as possibly representing a small hemorrhage versus asymmetric resorption of germinal matrix. Given that the clinical suspicion for hemorrhage was low, the infant was monitored closely with plans to repeat head ultrasonography if any neurologic changes were noted. She was evaluated by the orthopedic surgery team after radiography confirmed her absent bilateral radii and they recommended outpatient follow-up to evaluate for forearm splints. She was discharged on the third day after birth with a plan for weekly serial platelet monitoring and pediatric hematology follow-up scheduled for 2 days after discharge.The infant presented at 13 days of age to the emergency department with a small amount of blood in the stool for 3 consecutive stools. She was noted to have a platelet count of 41 × 103/µL (41 × 109/L) at this time and was given a transfusion of 10 mL/kg of platelets. The etiology of bloody stools was felt to be a milk protein allergy, which is a common feature of TAR syndrome. (5) At 1 month of age, the patient presented with jaundice and was found to have acute liver failure of unknown etiology. She was admitted and evaluated by the transplant team and underwent an uneventful orthotopic liver transplantation. Her postoperative course was complicated by biliary stricture and acute rejection. She was reevaluated for possible repeat orthotopic liver transplantation but due to her severe illness, she was not a candidate and died at 8 months of age.TAR syndrome should be suspected in patients with bilateral absent radii, with the presence of thumbs and thrombocytopenia (defined as platelet count <50 × 103/µL [<50 × 109/L]), when the cause of thrombocytopenia is thought to be a decreased number of megakaryocytes. (4)(5)(6)(7) It occurs in less than 1 in every 100,000 births. (4)(5)(6) There is a paucity of data available on prenatal diagnosis. Most of these patients are first noted to have the characteristic physical features during anatomy scan in the second trimester. (2)(3)(4) The classic findings described include limb anomalies, upper more frequent than lower, most commonly showing absence of bilateral radii, thumbs in flexion, and possible syndactyly. (1)(3)(4) In addition, cardiac anomalies with septal defects are more common, renal anomalies and other bony abnormalities are rare but can occur with TAR syndrome. (3)(5)Once these findings are evident, clinicians can turn to amniocentesis to evaluate for genetic variants or chromosome abnormalities in the fetus. It is important to note that to diagnose a patient with TAR syndrome, thrombocytopenia (as defined previously) is required as well as genetic testing that shows a heterozygous null allele in trans with a heterozygous RBM8A hypomorphic allele. (4) TAR syndrome has an autosomal recessive pattern of inheritance. (3)(4) This null allele is usually a deleted 200-kb region on the first chromosome at 1q21.1. (3)(4)(8)(9) Recommended genetic studies include a targeted genetic test for the gene RBM8A, to include deletion, duplication, and sequencing, along with a multigene panel (1)(3)(4)(8) to rule out other disorders that may present with the absence of a radial bone, such as Fanconi anemia, Roberts syndrome, and Holt-Oram syndrome (Table). (4)(10) If the previous 2 studies fail to obtain a diagnosis, then whole exome sequencing and whole genome sequencing may be considered to evaluate further for other genetic disorders. (1)(4)(9) Note that there does not appear to be a standardized protocol to evaluate for thrombocytopenia in utero. A multidisciplinary care conference to discuss the risks and benefits of cordocentesis versus conservative surveillance imaging is imperative. The advantage of performing cordocentesis is to help confirm the diagnosis, which may help some families obtain clarity about the future; however, there exists the risk of fetal death due to iatrogenic bleeding.For patients with TAR syndrome, management should begin before thrombocytopenia is ever noted. In short intervals, conservative surveillance prenatal ultrasonography can monitor for intracranial hemorrhage without placing the infant at risk of death. (4)(6) As occurred in our patient, coordination for scheduled cesarean section as close to term as possible, with no use of vacuum or forceps, is important. (3)(6) Planning to have neonatology and maternal-fetal medicine team and a point-of-care CBC analyzer to perform hemoglobin and platelet counts in the delivery room may expedite the treatment. The thrombocytopenia in TAR syndrome is described as a platelet count usually less than 50 × 103/µL (50 × 109/L) with severe cases usually around 14 to 20 × 103/µL (14-20 × 109/L). (3)(4)(6)Once the infant is born, it is imperative to obtain central intravenous access, given the potential lack of upper extremity access sites, to avoid multiple intravenous sticks. The hemoglobin and platelet count should be measured as soon as access is established. (4)(5) Platelet transfusions should be readily available in the delivery room, aiming to keep platelet count in a hemostatic range for the newborn. (3)(4)(5)(7) It is important to note that the hematology team should be consulted if the platelets are not rising appropriately and if multiple transfusions are needed because of the increased risk of alloimmunization, infection, or transfusion reaction in patients with TAR syndrome. (4) Echocardiography and renal ultrasonography are recommended to rule out organ anomalies once the patient is stabilized. (4) In addition, orthopedic surgery should be consulted to help evaluate for potential interventions for these patients. (4)(11)(12) The orthopedic surgery team can provide treatments that range from prosthesis, orthoses, and surgical intervention at times. (4)(9)(12)In most patients with TAR syndrome, thrombocytopenia is temporary, with levels returning to normal shortly after birth without therapy. (1)(3)(4) Despite this, patients’ symptoms can vary from normalization of platelets to continuous low levels. (1)(4) Surveillance is usually not warranted after platelet levels normalize. (4)(6) After resolution of thrombocytopenia, if the pediatrician or family members notice that the patient has had more frequent bruising or signs of petechiae, the platelet count should be checked again to rule out recurrent thrombocytopenia. (4)(6) It is important to note that cow milk allergy can be commonly seen in patients with TAR syndrome. (2)(4) Exacerbation of thrombocytopenia sometimes can be observed after affected patients consume cow milk and thus, avoidance of cow milk is sometimes recommended. (4)(5)(12)We describe this rare patient presentation with specific lessons learned about prenatal, delivery, and postnatal care that is unique to children with TAR syndrome. The prenatal aspect of TAR involves preoperative planning, coordination to provide multidisciplinary care, and surveillance. The birth aspect of TAR syndrome is careful delivery with no delay in diagnosis or treatment of thrombocytopenia. Patients with TAR syndrome require close postnatal surveillance of both intracerebral hemorrhage and platelet counts.Rethinking Congenital Heart Disease in Preterm Neonates 1. D; 2. A; 3. B; 4. B; 5. CCardiopulmonary Resuscitation with an Intact Umbilical Cord 1. D; 2. A; 3. B; 4. E; 5. C