Prenatal ultrasound diagnosis of thrombocytopenia with absent radii

Thrombocytopenia absent radius syndrome with Tetralogy of Fallot: a rare association

Thrombocytopenia absent radius (TAR) syndrome is a very rare and infrequently seen congenital disorder with an approximate frequency of 0.42/100,000 live births. It is associated with bilateral absence of radii, hypo-megakaryocytic thrombocytopenia, and presence of both thumbs. The other systems which are affected by TAR syndrome include skeletal, hematologic, and cardiac systems. Intracranial hemorrhages due to thrombocytopenia and cardiac disorders are a common association usually seen with this syndrome and are usual cause of death. We describe a 3-month-old infant who was diagnosed with TAR syndrome on the basis of clinical features (thrombocytopenia and bilateral absent radius bone and confirmed by genetic analysis). The patient was diagnosed to have Tetralogy of Fallot, for which the infant was managed with definitive repair and thrombocytopenia was managed with platelet transfusion. Infants with TAR syndrome should be assessed for other associated malformations of various systems and followed up regularly and parents should be counseled for associated expected complications in these patients. We report an infant with TAR syndrome with Tetralogy of Fallot, which has not been reported in medical literature until now and this is the first case of its type.

Prenatal diagnosis and post-mortem examination in a fetus with thrombocytopenia-absent radius (TAR) syndrome due to compound heterozygosity for a 1q21.1 microdeletion and a RBM8A hypomorphic allele: a case report

Background

Thrombocytopenia–absent radius syndrome is a rare autosomal recessive disorder characterized by megakaryocytic thrombocytopenia and longitudinal limb deficiencies mostly affecting the radial ray. Most patients are compound heterozygotes for a 200 kb interstitial microdeletion in 1q21.1 and a hypomorphic allele in RBM8A, mapping in the deleted segment. At the moment, the complete molecular characterization of thrombocytopenia–absent radius syndrome is limited to a handful of patients mostly ascertained in the pediatric age

Case presentation

We report on a fetus with bilateral upper limb deficiency found at standard prenatal ultrasound examination. The fetus had bilateral radial agenesis and humeral hypo/aplasia with intact thumbs, micrognathia and urinary anomalies, indicating thrombocytopenia–absent radius syndrome. Molecular studies demonstrated compound heterozygosity for the 1q21.1 microdeletion and the RBM8A rs139428292 variant at the hemizygous state, inherited from the mother and father, respectively

Conclusion

The molecular information allowed prenatal diagnosis in the following pregnancy resulting in the birth of a healthy carrier female. A review was carried out with the attempt to the trace the fetal ultrasound presentation of thrombocytopenia–absent radius syndrome and discussing opportunities for second-tier molecular studies within a multidisciplinary setting.

Multiple congenital contractures (congenital multiple arthrogryposis)

Arthrogryposis, is the occurrence of joint contractures of variable etiology that start prenatally. Arthrogryposis may result from neurologic deficit, neuromuscular disorders, connective tissue abnormalities, amniotic bands, [figure: see text] or fetal crowding. Arthrogryposis may result from no apparent hereditary causes (neuropathic, for example) or may be the result of hereditary factors (myopathic form, for example). Ultrasound diagnosis depends on observation of scant or absent motion of fetal extremities. Prognosis depends on the specific etiology of the contractures.

Prenatal diagnosis of thrombocytopenia absent radius (TAR) syndrome and vaginal delivery

A fetus with bilateral radial aplasia was identified on routine ultrasound. The diagnosis of thrombocytopenia absent radius (TAR) syndrome was confirmed with cordocentesis. The differential diagnosis of radial aplasia and prenatal tests available to assist with management are discussed. Cordocentesis offered useful information in the management of this case for both diagnosis and in deciding the route of delivery. We believe our case represents the first prenatal diagnosis of TAR syndrome in which vaginal delivery of a liveborn infant was intentionally allowed. Caesarean delivery may not be necessary for all fetuses diagnosed with TAR syndrome.

Prenatal evaluation and in utero platelet transfusion for thrombocytopenia absent radii syndrome

A fetus with absent radii in both forearms was discovered on routine ultrasound examination performed at 18 weeks of pregnancy. No other significant abnormalities were found, and no signs of haemorrhage were detected. Serial ultrasound examinations revealed no evidence of fetal internal bleeding. At 37 weeks of pregnancy, a CBC obtained by cordocentesis under ultrasound guidance confirmed the diagnosis of thrombocytopenia absent radii (TAR) syndrome. Apheresis platelets were transfused into the umbilical vein to correct the thrombocytopenia and was followed by an uncomplicated delivery. No bleeding was encountered during the remainder of the baby's neonatal course. We conclude that TAR syndrome can be readily identified prenatally on sonogram, and if severe thrombocytopenia is confirmed by cordocentesis, platelets should be transfused to diminish the risk of serious internal bleeding during and immediately after delivery.

Prenatal ultrasound diagnosis of Apert's syndrome

A mother affected with Apert's syndrome was diagnosed by ultrasound scan at 16-17 weeks to have a fetus similarly affected. The typical features of acrocephaly and symmetrical syndactyly were seen. This is probably the first time that this condition has been diagnosed at such a gestation by ultrasound scan. The patient decided to continue the pregnancy, and intrauterine death occurred at 34 weeks. The diagnosis was confirmed by pathological examination.

Prenatal diagnosis of thrombocytopenia absent radius syndrome by ultrasound and cordocentesis

The prenatal diagnosis of thrombocytopenia absent radius (TAR) syndrome, utilizing ultrasound and cordocentesis, is described. To our knowledge, this represents the first prenatal diagnosis of this condition in an index case. The diagnostic evaluation of a fetus with upper extremity limb reduction defects is discussed.

Clinical manifestations of the thrombocytopenia and absent radii (TAR) syndrome

Six patients with the classical features of the TAR syndrome were diagnosed at birth. In one case an older sibling was also affected. The characteristic features of foreshortened forearms and radially deviated hands were noted in all cases at presentation and confirmed radiologically. With one exception skeletal abnormalities of the lower limbs were also present. Varying degrees of thrombocytopenia were present at birth with three of the five patients having platelet counts below 50 x 10(9)/L. Bone marrow examination was performed in two patients and revealed an absence of normal megakaryocytes. Two patients with severe thrombocytopenia had bleeding complications during infancy requiring transfusion support. Severe gastroenteritis occurred in two patients, in one of whom it was attributed to cow's milk intolerance. In all patients the platelet count has risen progressively since birth. Orthopedic surgical procedures have been performed without hemorrhagic complications.

Thrombocytopenia with absent radius in a boy and his uncle

We report a boy and his maternal uncle who have Thrombocytopenia-Absent Radius (TAR) syndrome. The mother of the propositus is normal. A maternal aunt has mild radial hypoplasia, possibly representing partial expression of the syndrome. A review of the literature shows several pedigrees in which relatives other than sibs were affected with TAR. Thus, autosomal recessive inheritance may not account for all cases and alternate modes of transmission should be considered.

[Fetal biometry: review and application of sex determination]

Diagnostic ultrasound was introduced in the practice of obstetrics through its ability to measure accurately the biparietal (DBP) diameter of the foetus. The development of bidimensional and grey tone images expanded the possibility of fetal biometry. One of its most important uses is the estimation of gestational age. A knowledge of foetal age is necessary to interpret the results of most of the investigations currently performed during pregnancy. Different fetal dimensions increase with age at different rates according to the period of gestation. During the embryonic period, the crown-rump length gives a very good estimation of age within 4-6 days for twice the standard deviation. Later on, because of the curvature of the fetus, the age is estimated with the DBP. The accuracy diminishes with the slowing down of fetal growth, from 12 weeks onwards, when twice the standard deviation of the age estimate may be as long as 2 weeks. When DBP is no longer reliable in determining age, femur length is measured being more reliable for that purpose at least till 24 weeks. A very early assessment of foetal age reduces the risk of errors in estimating the duration of pregnancy and is important to detect early growth retardation (IUGR); this is usually symmetric, i.e. affecting all fetal parts (versus asymmetrical or late IUGR where trunk growth is first involved). Fetal weight can be estimated by fetal parts measurements. A formula was derived as long as twenty years ago but not all authorities agree on any measuring technique as evidenced by the many different formulas proposed--a sign that no very satisfactory one yet exists.(ABSTRACT TRUNCATED AT 250 WORDS)

Prenatal ultrasound detection of humero-radial synostosis in a case of Antley-Bixler syndrome

The Antley-Bixler syndrome is characterized by multiple skeletal fusions including humero-radial synostosis, anterior bowing of the femora, cardiac and renal malformations and a high incidence of early postnatal lethality. In the pregnancy of a mother who had previously given birth to a child with the Antley-Bixler syndrome, prenatal ultrasound diagnosis was performed at 17 and 20 weeks. Fixed flexion of about 80 degrees in both elbows was seen together with humero-radial synostosis and bowing of the ulnae. The fetus performed jerky craniocaudal movements in its shoulders, but did not, during five hours of real-time observation, move at all in the elbows. Mild anterior bowing of the femora was also observed. The pregnancy was terminated at 21 weeks, and radiological examination of the female fetus confirmed the above mentioned findings including complete bilateral humero-radial synostosis. She also had cardiac and renal malformations. An ultrasound diagnosis of syndromes which have humero-radial synostosis as one feature is possible. Immobility and flexion in the elbows during a long period is probably the essential diagnostic finding.