Rare disease ‘GNB1 Encephalopathy

In News: Researchers at the Indian Institute of Technology (IIT), Madras, Tel Aviv University and Columbia University are studying a rare genetic brain disease called “GNB1 Encephalopathy” and trying to develop a drug to treat it effectively.

GNB1 Encephalopathy

• It is a kind of brain disease or neurological disorder which affects individuals in the foetus stage.
• With less than 100 documented cases worldwide
• Children born with GNB1 mutation experience delayed physical and mental development, intellectual disabilities, epilepsy (abnormal brain activity), movement problems, muscle hypotonia or hypertonia.
• A potassium channel called G-protein gated Inwardly Rectifying K+ (GIRK) channel (present in brain, heart and endocrine glands) function is affected significantly.
• As I80T mutation is the most prevalent variant in GNB1 encephalopathy patients.

How it occurs:

• A single nucleotide mutation in the GNB1 gene that makes one of the G-proteins, the “Gβ1 protein,” causes Encephalopathy.
• Every cell in the human body has a wide variety of signalling molecules and pathways that help in communicating with other cells and within itself.
• The major signalling mechanism used by cells is ‘G-Protein Coupled Receptor’ (GPCR) signalling.
• GPCR is a receptor that receives a signal (e.g. a hormone, light, neurotransmitter) from the outside of the cell and transduces it to the inside of the cell.
• GPCR is present in the cell membrane and has a G-protein (αβγ) attached to it from inside the cell.
• G-proteins are the immediate downstream molecules that relay the signal received by the GPCR.
• These G-proteins are present in every cell, and any malfunction will cause disease.

Treatment:

• As the developmental issues start at the fetal stage, gene therapy is the most plausible option to alleviate the effects of the mutation.

• Whole genome sequencing, the elucidation of the full genetic analysis of the baby, can be very helpful in early diagnosis of the disease.
• Epilepsy can be treated using specific drugs to increase the patient’s quality of life.
• To treat epilepsy, specific targets have to be identified.
• Most epilepsies are caused due to altered ion channel function.
• Ion channels are proteins that underlie the electrical activity of neurons and heart cells.

Source: The hindu

Previous Year Questions

Q.1) In the context of hereditary diseases, consider the following statements: (2021)

1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of egg.
2. A child inherits mitochondrial diseases entirely from mother and not from father.

Which of the statements given above is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2