Health encyclopaedia - Alphabetical Topic List健康百科全书-按字母顺序排列的主题清单

| A | | 1 | | B | | b | | C | | 人才招聘 | | D | | | | E | | 电子 | | F | | f | | G | | 克 | | H | | h | | I | | 我 | | J | | j | | K | | k | | L | | 升 | | M | | 米 |
| N | | n | | O | | o | | P | | p | | Q | |常见问题 | | R | | 研究 | | S | | | | T | | 吨 | | U | | u | | V | | v | | W | | 瓦特 | | X | | x | | Y | | y |

Causes of Haemophilia原因血友病

Haemophilia A is due to the absence of Factor VIII.血友病A是由于缺乏因子VIII 。 Haemophilia B is due to absence of Factor IX.血友病B是由于缺乏因子IX 。 These clotting factors are two of the many elements necessary for normal blood coagulation.这些凝血因子是两个的众多因素所必需的正常的凝血功能。

The disease is passed from mother to son on the X chromosome.这种疾病是通过由母亲传染给儿子，对X染色体上。 (The father passes a Y chromosome to their son). （父亲通过对Y染色体，以他们的儿子） 。 Thus women can be carriers having one affected chromosome and transmitting the disease to 50 per cent of their male offspring.因此，妇女可以运营商之一，受影响的染色体和转递疾病的50 ％ ，其雄性后代。

In about 30 per cent of cases, however, there is no family history of haemophilia, these cases arise as a result of new mutations occurring in the cells that produce eggs or sperms in the parents.在大约30 ％的情况下，不过，有没有家族病史，血友病，这些个案出现，由于新的基因突变发生在细胞产生卵子或精子在家长。

The severity of haemophilia varies with the level of Factor VIII activity in the individual and in severe cases this may be less than two per cent of normal.严重的血友病不同水平的因子VIII活动在个人和在严重的情况下，这可能是不到两年的百份之正常。