Mutations in the IL2RG gene cause approximately 30 percent of severe combined immunodeficiency disorder (SCID) cases in humans. These mutations result in alterations to a protein component of cytokine receptors that are essential for proper development of the immune system. The IL2RG gene is composed of eight exons and contains upstream and downstream sequences that are necessary for proper transcription and translation. Below are some of the mutations observed. For each, explain its likely influence on the IL2RG gene product (assume its length to be 375 amino acids).

Deletion in Exon 2, in frame

Key Concepts

IL2RG Gene Function

The IL2RG gene encodes a protein that is a critical component of cytokine receptors, which are essential for the signaling pathways that regulate immune cell development and function. Mutations in this gene can disrupt these pathways, leading to severe combined immunodeficiency (SCID), a condition where the immune system is severely compromised.

Types of Mutations

Mutations can be classified into several types, including deletions, insertions, and point mutations. A deletion in Exon 2, particularly if it is in-frame, means that a portion of the coding sequence is removed without altering the reading frame, potentially leading to a shorter but functional protein, depending on the specific amino acids deleted and their role in the protein's function.

Impact of Mutations on Protein Function

Mutations can significantly affect the structure and function of proteins. In the case of the IL2RG gene, a deletion in Exon 2 may alter the protein's ability to interact with other molecules or perform its role in immune signaling, which can lead to impaired immune responses and increased susceptibility to infections.