Absent thumb, radial deviation of wrist, bowing of forearm with thrombocytopenia which investigation need not to be done ?
Echocardiography
Bone marrow examination
Platelet count
Karyotyping
Characteristic features such as absent thumb and thrombocytopenia suggests Fanconis anemia.
FEATURES OFFANCONISANEMIA

Skin pigment change        --> Darkened areas of the skin, cafe-au-lait spots, vitiligo
Upper limb                          --> Absent or hypoplastic thumb, absent or hypoplastic radii, dysplastic ulnae, clinodactyly
Gonads                                —> Abnormal or atrophic testis
Head and face                    -p Microcephaly, sprengels deformity, spina bifida
Kidneys                                —+ Ectopic or pelvic, horseshoe, hypoplastic or dysplastic
Abnormal eyes/eyelid
Hematological abnormalities

Pancytopenia+ thrombocytopenia and neutropenia these are the most common and most serious symptoms of
Fanconis anemia.

one marrow failure            ---> Its a major complication of Fanconis anemia
Acute myeloid leukemia ---> Fanconis anemia have elevated risks of developing acute myeloid leukemia.
Myelodysplastic syndromes —> Increased risk of myelodysplastic syndrome in Fanconis anemia.

Common tests for Fanconis anemia include : 

Complete blood count (CBC) o Bone marrow biopsy                   o Chromosomal breakage analysis
HLA tissue typing                      o Hearing test                                  o Hand X-ray and other imaging studies
Developmental test                   o Ultrasound of the kidneys     
 Amniocentesis or chorionic vinous crimpling