Lanadelumab in FXII-associated Cold Autoinflammatory Syndrome (FACAS)

Inclusion Criteria: * Adolescents (12 - 17 years) and adults (18 years or older) * Documented FXII-associated autoinflammatory disorder (FACAS) by positive genetic analysis result * Clinical symptoms of cold-associated wheals, arthralgia, headache, fatigue (FACAS) * Able to read, understand and willing to sign the informed consent form and abide with study procedures * Males and females who are fertile and sexually active must adhere to contraception requirements for the duration of the study as follows: * Females of childbearing potential must agree to be abstinent or else use any two of the following medically acceptable forms of contraception from the screening period through 30 days after the final study visit: progestin-only oral contraceptive, condom with or without spermicidal jelly, diaphragm or cervical cap with spermicidal jelly, or intra-uterine device (IUD, all types). Female participants whose male partner has had a vasectomy must agree to use one additional form of medically acceptable contraception. * Females of non-childbearing potential, defined as surgically sterile (status post hysterectomy, bilateral oophorectomy, or bilateral tubal ligation) or post-menopausal for at least 12 months do not require contraception during the study. * Males, including males who are surgically sterile (post vasectomy), with female partners of childbearing potential must agree to be abstinent or else use a medically acceptable form of contraception from the screening period through 60 days after the last IMP injection. Exclusion Criteria: * 1\. Any other forms of urticaria or angioedema not related to genetic mutations within the FXII gene 2. Concurrent/ongoing treatment with biologics or recent treatment (less than 5 half-lives) 3. Concurrent/ongoing treatment with anakinra within 7 days prior to screening, with canakinumab within 100 days prior to screening 4. Concurrent/ongoing treatment with oral/parenteral corticosteroids greater than 10 mg/d within 2 weeks prior to screening 5. Concurrent/ongoing treatment with other immunosuppressives within 4 weeks or 5 half-lives prior to screening, whichever is longer 6. Treatment with a live (attenuated) virus vaccine within 4 weeks prior to Baseline visit 7. Exposure to angiotensin-converting enzyme (ACE) inhibitors or any estrogen-containing medications with systemic absorption (such as oral contraceptives or hormonal replacement therapy) within 4 weeks prior to screening. 8\. Use of prophylactic therapy with C1-INH, attenuated androgens, or antifibrinolytics within 2 weeks prior to the start of the treatment period (Day 0). 9\. Any of the following liver function test abnormalities: * alanine aminotransferase (ALT) \> 3x upper limit of normal, or * aspartate aminotransferase (AST) \> 3x upper limit of normal, or * total bilirubin \> 2x upper limit of normal (unless the bilirubin elevation is a result of Gilbert's Syndrome). 10\. Pregnancy or breastfeeding. 11. Subject has any condition that, in the opinion of the Investigator or Sponsor, may compromise their safety or compliance, preclude successful conduct of the study, or interfere with interpretation of the results (e.g., history of substance abuse or dependence, a significant pre-existing illness or other major comorbidity that the Investigator considers may confound the interpretation of study results). 12\. Significant medical condition rendering the patient immunocompromised or not suitable for a clinical trial. 13\. Enrollment in another investigational treatment or device study or use of an investigational agent, or less than 4 weeks or 5 half-lives, whichever is longer, since end of another investigational device or drug trial. 14\. Patients with known hypersensitivity to any constituent of the products of lanadelumab. 15\. Dementia, altered mental status, or any psychiatric condition, or stay in an institution further to an official or court order that would prohibit the understanding or rendering of informed consent or participation in the study. 16\. Subjects who are study site employees, or immediate family members of a study site or sponsor employee.