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Please enable JavaScript. Thrombocytopenia with absent radius TAR syndrome is a rare autosomal recessive congenital disorder characterised by bilateral absence of radius bone and a reduced platelet count [ 1 ]. It has an incidence of 0. TAR syndrome has no gender, ethnic or racial predilection.
TARS could be associated with other gastrointestinal, skeletal, hematologic, and cardiac anomalies [ 3 ]. Haemorrhage, a major cause of death, occurs commonly in the first 14 months of life. This is a rare case of TAR syndrome with typical presentation. A 6-hour old female neonate referred to the radiology department for X-ray of both upper limbs on account of bilateral upper limb deformity from birth. No history of birth trauma, birth asphyxia, family history of similar or other congenital limb deformity.
There was attempted termination of pregnancy with the use of a hormonal contraceptive pills levonorgestrel, dose unknown and herbal concoctions in the first trimester of pregnancy. She was delivered via spontaneous vaginal delivery at term by a year-old unmarried primigravida. Patient had a birth weight of 2. Musculoskeletal system revealed increased tone in the upper limbs compared to lower limbs.
No other abnormality was detected in other systems. Plain radiograph of both upper limbs reveals bilateral absent radii, shortening and bowing of the ulna, abnormal flexion and radial deviation of both hands Figure 1. Other bones of the upper limbs are present and demonstrate no abnormality. No deformity is seen in other parts of the body. Abdominal ultrasound revealed normal abdominal organs. Radiograph of both upperlimbs showing absence of radius bilaterally and ulnar deviation of the hand. TAR syndrome is a rare autosomal recessive disorder.
It is an inherited syndromic thrombocytopenia that is consistently associated with skeletal abnormality and thrombocytopenic haemorrhage. It has no gender preference but some studies have reported female's predilection [ 1 ]. Like in the index case, 2 previous reports of TAR syndrome by Musa et al.
The cause of the thrombocytopenia is still unclear. However, several theories have been proposed. The widely acceptable theory is the failure in production of humoral or cellular stimulators of megakaryocytopoiesis. Alterations of the RBM8A gene involving a microdeletion on chromosome 1q This was however, not assessed in the index case for paucity of facility for molecular studies.
Conspicuous in this report is the use of levonogestrel and herbal concoctions content of which was not known. This case report buttresses the teratogenic effect of drugs and chemicals especially during the first trimester as in this case. The platelet count is frequently less than 50, with normal platelet morphology peripheral blood film examination. Other associated haematological features are eosinophilia, leukocytosis with a left shift. The WBC count in this case was normal. Learn More.
Thrombocytopenia with absent radii TAR syndrome is a rare genetic syndrome that occurs with a frequency of about 0. It is characterized by hypo-megakaryocytic thrombocytopenia with bilateral absent radii and the presence of both thumbs. The thrombocytopenia is initially very severe, manifesting in the first few weeks to months of life, but subsequently improves with time to reach near normal values by one to two years of age.
We present a case of a newborn with TAR syndrome with an atypical presentation of mild thrombocytopenia in the first week of life, with early normalization of platelet counts in the neonatal period. Additionally, the absence of hypo-megakaryocytes on peripheral smear sets this patient apart from the typical cases of TAR syndrome.
TAR syndrome is often associated with significant morbidity and mortality secondary to severe thrombocytopenia, which occurs with the highest frequency in the first 14 months of life. The most common cause of mortality is due to a severe hemorrhagic event occurring in the brain, gastrointestinal tract, and other organs.
Therefore, all patients with TAR syndrome should be monitored closely for symptomatic thrombocytopenia with platelet transfusions being implemented as the first-line therapy for the treatment of severe or symptomatic disease. Thrombocytopenia with absent radii TAR syndrome is a rare congenital defect characterized by thrombocytopenia with specific skeletal abnormalities, primarily of the upper limbs. It was first characterized as a syndrome by Hall et al.
The presence of both thumbs is a characteristic feature that distinguishes TAR syndrome from other conditions associated with similar skeletal abnormalities such as Fanconi anemia and Holt-Oram syndrome. The overall prevalence of TAR syndrome is estimated to be ,, [ 2 ]. We report a rare case of a newborn with a diagnosis of TAR syndrome without significant thrombocytopenia. A full-term, appropriate-for-gestational-age female neonate was admitted to the neonatal intermediate care unit at the Woodhull Hospital for observation due to prenatal concerns for a possible diagnosis of TAR syndrome.
The neonate was born to a year-old G6P female who received early and adequate antenatal care at a prenatal clinic at the Wyckoff Hospital. The mother took prenatal vitamins throughout the course of her pregnancy.
Routine maternal serology was unremarkable, including a Quad screen done at 17 weeks of gestation. However, a prenatal sonogram performed at 22 weeks of gestation, and an amniocentesis at 26 weeks of gestation had findings suggestive of TAR syndrome. The exact findings were not readily available since the prenatal care was done at an outside facility. The pregnancy course was significant for a urinary tract infection UTI in the second trimester, which was successfully treated with nitrofurantoin.
Additionally, the mother developed preterm contractions at 33 weeks of gestation and was hospitalized for two days. She received antenatal steroids for fetal lung maturation, magnesium sulfate for neuroprotection, and antibiotic coverage due to her group B streptococcus GBS unknown status. She was subsequently discharged and re-admitted at 38 weeks of gestation in active labor.
The neonate was delivered via elective cesarean section due to concerns of a possible low platelet count in the neonate secondary to TAR syndrome. The neonate received routine resuscitation at birth, and had a birth weight of g, length 48 cm, and head circumference of There was also syndactyl of the digits of the left hand and a web between the thumb and 4th digit.
No abnormality of the lower extremities was noted. The ears were noted to be low set bilaterally, but the infant had no other dysmorphic features. Examination of all other systems were within normal limits. Postnatal evaluation included serial platelet monitoring, peripheral smear, X-rays of the upper extremities, abdominal ultrasound, echocardiogram, and genetic studies. Imaging studies included an abdominal ultrasound and an echocardiogram. The abdominal ultrasound was done to evaluate the kidneys which appeared normal in size and echotexture, without evidence of hydronephrosis.
The echocardiogram showed a small patent foramen ovale PFO with left to right shunt, but was otherwise normal. Genetic testing was performed with findings of a normal female karyotype 46 XX on chromosomal analysis and a pathogenic deletion of 2. The neonate was started on expressed breast milk and formula soon after birth. A hypoallergenic formula was given, per Pediatric Hematology recommendation, due to the association between TAR syndrome and cow milk protein allergy.
No evidence of bleeding or other clinical manifestations of thrombocytopenia was noted. The hyperbilirubinemia was accompanied by a high reticulocyte count max The neonate was eventually discharged on day 9 of life, with appointments for follow up with Pediatric Hematology, Genetics, and Orthopedics.
At present, the patient continues to be followed up in the outpatient clinic with ongoing monitoring of the platelet count. Additionally, the patient was reviewed by Orthopedics who recommended reconstructive surgery at one year of life. TAR syndrome is a rare congenital defect characterized by hypo-megakaryocytic thrombocytopenia and bilateral radii aplasia or hypoplasia in the presence of both thumbs. The presence of both thumbs distinguishes TAR syndrome from other conditions associated with phocomelia, such as Fanconi anemia and Holt-Oram syndrome.
The etiology of TAR syndrome is unknown, however, a study by Klopocki et al. This microdeletion in the long q arm of chromosome 1 usually involves deletion of a gene called the RBM8A gene. However, this microdeletion alone is not enough to cause the onset of TAR syndrome. TAR syndrome usually occurs when the chromosome 1q The presence of an RBM8A hypomorphic allele in conjunction with the 1q Co-inheritance of the 1q
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