Nezelof's syndrome

Nezelof's syndrome is a rare primary immunodeficiency characterized by severe T-cell lymphopenia and impaired cellular immunity, often with normal or near-normal immunoglobulin levels. Patients typically present with recurrent and severe infections, particularly opportunistic infections, due to the profound T-cell dysfunction. It is a form of severe combined immunodeficiency (SCID) with preserved B-cell function.

This code is appropriate for documenting a diagnosis of Nezelof's syndrome based on clinical presentation, immunological findings (e.g., low T-cell counts, impaired T-cell function), and genetic testing if performed. Use this code when the medical record clearly indicates this specific primary immunodeficiency, distinguishing it from other forms of SCID or immunodeficiencies.

• Ensure documentation specifies "Nezelof's syndrome" or provides sufficient detail to differentiate it from other SCID types.
• Do not confuse with other primary immunodeficiencies that involve both B-cell and T-cell defects.
• Consider sequencing this code as the primary diagnosis when it is the reason for the encounter, especially for management of related complications.