Rewriting the code: a One-Time gene fix for a rare immune disease?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: * Aged \>= 3 years and weighing \>=15 kg. * Confirmed CXCR c.1000C\>T, pR334X mutation. * Ability to undergo apheresis for stem cell collection. * Medical lab data (historical) of neutropenia, or B cell dysfunction (low or absent IgG levels, or on IV gamma globulin. * Expected survival of at least 120 days. * Must be willing to have blood and tissue samples stored. * Participants of reproductive potential must agree to consistently use effective contraception from start of busulfan conditioning through at least one-year post-treatment. Acceptable forms of contraception are: * Hormonal contraception in continuously effective use. * Male or female condom with spermicide as indicated. * Diaphragm or cervical cap in consistent and effective pattern of use with a spermicide. * Intrauterine device in-situ EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: * Acute onset infection as indicated by symptoms such as persistent fevers, or imaging (new pneumonia on CT for example), isolated pathogen and requiring medical intervention. * Severe liver dysfunction with transaminases \> 6 fold upper limit will be excluded until approval by hepatology consult who will provide mitigating plans for liver protection. * Renal dysfunction-serum creatinine \>3.0 x ULN. * Coagulation dysfunction- Prothrombin INR or Partial thromboplastin time \>2 x ULN (patients on controlled anticoagulation agents will not be excluded for therapeutic levels). * Known hypersensitivity to busulfan or any component of the product. * Contraindications for administration of busulfan, including but not limited to: hypersensitivity, chronic lymphocytic leukemia, acute leukemia in blastic crisis, pregnancy, or lactation. * Childhood malignancy (occurring before 18 years of age) in the participant or a first degree relative, or previously diagnosed known genotype of the participant conferring a predisposition to cancer unless approved by the with appropriate consultants and approved by the study PI (no DNA or other testing for cancer predisposition genes will be performed as part of the screen for this protocol). * Any other condition that, in the opinion of the investigator, may compromise the safety or compliance of the participant, or would preclude the participant from successful study completion.