FANCB is the one exception to FA being autosomal recessive, as this gene is on the X chromosome. These genes are involved in DNA repair.The carrier frequency in the Ashkenazi Jewish population is about one in 90. Genetic counseling and genetic testing are recommended for families who may be carriers of Fanconi anemia.Because of the failure of hematologic components—white blood cells, red blood cells, and platelets—to develop, the bodys capabilities to fight infection, deliver oxygen, and form clots are all diminished. Pathogenesis
Clinically, hematological abnormalities are the most serious symptoms in FA. By the age of 40, 98% of FA patients will have developed some type of hematological abnormality. However,  a few cases have occurred  in which older patients have died without ever developing them. Symptoms appear progressively, and often lead to complete bone marrow failure. While at birth, blood count is usually normal, macrocytosis/megaloblastic anemia, defined as unusually large red blood cells, is the first detected abnormality, often within the first decade of life (median age of onset is 7 years). Within the next 10 years, over 50% of patients presenting haematological abnormalities will have developed pancytopenia, defined as abnormalities in two or more blood cell lineages. This is in contrast to Diamond–Blackfan anemia, which affects only erythrocytes, and Shwachman–Diamond syndrome, which primarily causes neutropenia. Most commonly, a low platelet count (thrombocytopenia) precedes a low neutrophil count (neutropenia), with both appearing with relative equal frequencies.
A subconjunctival bleeding initially appears bright-red underneath the transparent conjunctiva. Later, the bleeding may spread and become green or yellow as the hemoglobin is metabolized. It usually disappears within 2 weeks. Causes
Mechanical
Increased venous pressure (e.g. extreme g-force, straining, vomiting, choking, coughing or strangling) or from straining due to constipation
External pressure changes:Atmospheric pressure changes due to aircraft altitude changes. Mask squeeze from diving without equalizing mask pressure during descent or from diving deeply in water
Eye injury
Head injury
Laser eye surgery or other eye surgery
Zygoma fracture (results in lateral subconjunctival bleeding)
Medical conditions that cause increased venous pressure:
Whooping cough or other extreme sneezing or coughing
Severe hypertension
Medical conditions that affect blood or blood vessels:
Certain infections of the outside of the eye (conjunctivitis) where a virus or a bacterium weaken the walls of small blood vessels under the conjunctiva
Coagulation disorder (congenital or acquired) including Ebola
Acute hemorrhagic conjunctivitis (caused by Enterovirus 70 or Coxsackie A virus)
LeptospirosisSubconjunctival bleeding in infants may be associated with scurvy (a vitamin C deficiency),abuse or traumatic asphyxia syndrome. Diagnosis
Diagnosis is by visual inspection, by noting the typical finding of bright red discoloration confined to the white portion (sclera) of the eye. Management
A subconjunctival bleeding is typically a self-limiting condition that requires no treatment unless there is evidence of an eye infection or there has been significant eye trauma. Artificial tears may be applied four to six times a day if the eye feels dry or scratchy. The elective use of aspirin is typically discouraged. References


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