Congenital myelopathies are very rare bone marrow diseases. They manifest initially in small or school age children.
There are a number of hereditary panmyelopathies, i.e., functional disorders of the bone marrow, that affect all 3 cell types (red and white cells as well as the thrombocytes). The most frequent are summarized as follows.
Blood clotting disorders
Congenital blood clotting disorders are caused by a genetic defect of the megakaryocytes (precursor of thrombocytes) or the plasmatic coagulation factors.
In the thrombocytopenias one distinguishes between two autosomal recessive hereditary forms:
- Amegakaryocytic thrombopenia
- Thrombocytopenia with radius aplasia
Today one knows many differing coagulopathies. Most of them are inherited autosomal recessively. The only exceptions are hemophilias A and B, which are X chromosomal recessively inherited.
Disorders of the lymph vessels
Primary lymphatic edema is subdivided into 3 groups:
- Congenital lymphatic edema is present already at birth: Milroy disease
- Somewhat later (mostly in adolescence but before age 35) lymphatic edema praecox commences: Meige disease
- Lymphatic edema tarda begins only after age 35