An infant shows congenital absent thumb, radial deviation of wrist and anterior bowing of radius. All are done as diagnostic procedures except a) Platelet count b) Karyotyping c) ECHO d) Bone marrow biopsy Ans d Radial club hand The forearm is foreshortened, and the wrist is positioned in radial deviation. It is associated with thumb hypoplasia/absence. Clinical presentation of radial clubhand varies with the degree of radial deficiency and the presence of associated anomalies. Radial deficiency is the classic anomaly that is associated with systemic conditions. All forms, regardless of the degree of expression, warrant systemic evaluation. Syndrome Characteristics Table : Syndromes associated with radial deficiency Holt-Oram Heart defects, most commonly cardiac septal defects TAR Thrombocytopenia-absent radius syndrome. Thrombocytopenia present at birth, but improves over time. VACTERL Vertebral abnormalities, anal atresia, cardiac abnormalities, tracheoesophageal fistula, esophageal atresia, renal defects, radial dysplasia, lower limb abnormalities Fanconi anemia Aplastic anemia not present at birth; develops at about 6 years. Fatal without bone marrow transplant. Chromosomal challenge test now available for early diagnosis. The appropriate workup for associated conditions necessitates referral to pediatric subspecialists. The heart is evaluated by auscultation and echocardiography. The kidneys are examined by ultrasound, and the platelet status is assessed by blood count and peripheral blood smear. The most devastating associated condition is Fanconi anemia. Children with Fanconi anemia do not have signs of bone marrow failure at birth; therefore, the diagnosis is not initially apparent. The majority of children experience signs of aplastic anemia between the ages of 3 and 12 years (median age of 7 years). However, a chromosomal challenge test is available that allows detection of the disease prior to the onset of bone marrow failure. This assay subjects a sample of the childâ€™s lymphocytes to diepoxybutane or mitomycin C, which cause chromosomes within Fanconi anemia cells to break and rearrange. Children with VACTERL syndrome warrant additional evaluation for spinal abnormalities, such as congenital scoliosis, and require radiographs of the spinal column. Children with VACTERL syndrome often appear similar to children with Fanconi anemia; they are of small stature, have feeding difficulties, and have similar musculoskeletal anomalies. Therefore, a chromosomal challenge test is warranted in a child with a presumed diagnosis of VACTERL syndrome. Special Investigations for Radial and thumb hypoplasia â€¢ Chromosome analysis â€“ basic G-banding to exclude trisomy 18, triplidy, del13q and other visible abnormalities. â€¢ Additional cytogenetic analysis for Fanconi anaemia, Robert syndrome, Baller Gerold syndrome â€¢ Hematological investigation â€“ full blood count, platelet analysis â€¢ Xray of the affected limb, consider chest and vertebral Xrays: vertebral abnormalities (VACTERL), cardiac enlargement, shoulder girdle(Holt Oram) â€¢ Cardiac ECHO and ECG â€“ especially in the presence of murmur or possibility of Holt Oram syndrome or if there is tracheo-esophageal fistula. â€¢ Renal USG â€“ VATER and fanconi anaemia About Thrombocytopenia with absent radii (TAR)Thrombocytopenia presents at birth and it improves with age. It is also a radial ray defect, the radii are absent but mostly thumb is normal. So our case is most probably not TAR syndrome. But still I feel thrombocytopenia needs to be ruled out as there can be slight variation in presentation of all syndromes. Hence in an infant with radial club hand platelet count, karyotyping and ECHO is warranted. Bone marrow biopsy is indicated for Fanconi anaemia which is a prominent cause of this deformity. But since it does not present before 6-7 yrs age it is not needed in an infant.