Griscelli syndrome type 2

A rare genetic disorder affecting pigmentation and immune function

Classification
External resources

Griscelli syndrome type 2 is a rare genetic disorder characterized by a combination of hypopigmentation and immunodeficiency. It is one of the three types of Griscelli syndrome, which are distinguished by their genetic causes and clinical features.

Genetics

Griscelli syndrome type 2 is caused by mutations in the RAB27A gene, which is located on chromosome 15. This gene is responsible for encoding a protein that is involved in the transport of melanosomes and other lysosome-related organelles within cells. The mutation leads to defects in the transport and distribution of these organelles, resulting in the characteristic symptoms of the syndrome.

Clinical Features

The hallmark features of Griscelli syndrome type 2 include:

• Hypopigmentation: Affected individuals often present with silvery-gray hair and light skin due to the abnormal distribution of melanin in the hair shafts and skin.
• Immunodeficiency: Patients have a compromised immune system, making them susceptible to recurrent infections. This is due to the impaired function of cytotoxic T cells and natural killer cells.
• Neurological symptoms: Some individuals may experience neurological problems, which can include developmental delay and seizures.

Diagnosis

Diagnosis of Griscelli syndrome type 2 is based on clinical evaluation, family history, and genetic testing to identify mutations in the RAB27A gene. Microscopic examination of hair shafts can reveal the characteristic clumping of melanin, which is a diagnostic feature.

Treatment

There is no cure for Griscelli syndrome type 2, and treatment is primarily supportive. Management of the condition involves:

• Infection control: Prophylactic antibiotics and immunoglobulin replacement therapy may be used to prevent infections.
• Hematopoietic stem cell transplantation (HSCT): This is the only definitive treatment that can correct the immunodeficiency and prevent the progression of neurological symptoms.

Prognosis

The prognosis for individuals with Griscelli syndrome type 2 varies. Without treatment, the condition can be life-threatening due to severe infections and neurological complications. Early diagnosis and treatment, particularly with HSCT, can significantly improve outcomes.

Related pages

• Griscelli syndrome
• Immunodeficiency
• Hypopigmentation
• Genetic disorder