Eligibility Criteria:
Inclusion Criteria:
* with telomeropathy defined by the existence of a deleterious constitutional mutation of a gene involved in telomere maintenance (TERT, TERC, DKC1, TINF2, RTEL1, PARN, ACD, NHP2, NOP10, NAF1, WRAP53, CTC1, ERCC6L2, USB1, POT1, DNAJC21 or a newly identified gene responsible for telomeropathy ),
* 15 years or older,
* with severe haematological involvement (platelets \< 20 G/L or ANC \< 0.5 G/L and/or hemoglobin \< 8 g/dL and/or transfusion needs) and/or pulmonary fibrosis with parenchymal involvement greater than 10% on the CT scan.
* being able to give informed consent for patients 18 years and older,
* being able to give consent and have the consent of the holder (s) of parental authority for children over 15 years,
* being a beneficiary of social security scheme.
Exclusion Criteria:
* with HIV infection or active hepatitis B or C infection,
* with severe hepatic disease: ASAT and/or ALAT \> 5N, or direct bilirubinemia \> 30 μmol/L, TP \<50% (except vitamin K deficiency),
* having an active or treated tumor pathology for less than 5 years with the exception of a basocellular carcinoma or a in situ carcinoma of the cervix,
* with a history of organ or hematopoietic stem cell transplantation or with an indication of hematopoietic stem cell or organ transplantation within 6 months of inclusion,
* with an absolute contraindication to treatment with danazol: active thrombosis or history of thromboembolic disease, porphyria, severe renal or cardiac insufficiency (NYHA stage III or IV), androgen-dependent tumor, uncharacterized mammary nodules, pathological genital hemorrhage of undetermined etiology,
* who have already received danazol for the treatment of telomeropathy,
* having received another androgen within a period of less than 6 months,
* receiving another experimental treatment,
* receiving another hormonal therapy,
* receiving simvastatin,
* having a pregnancy plan and not committing to effective contraception while taking the treatment,
* breastfeeding,
* under guardianship or curators.