Review Question - QID 106680

This patient is presenting with Chediak-Higashi syndrome (CHS) which is characterized by recurrent staphylococci/streptococci infections, partial albinism, and peripheral neuropathy (ex: nystagmus). CHS is caused by a defect in the LYST gene.

CHS is an autosomal recessive immunodeficiency which causes phagocyte dysfunction. It is caused by a defect in the lysosomal trafficking regulator (LYST) gene, which leads to microtubule dysfunction in phagocytes. Patient's often present with the "3 P's": Pyogenic infections (strep/staph), Partial albinism, and Peripheral neuropathy. Giant granules will often be observed in neutrophils on a peripheral blood smear as seen in Figure B.

Reust reviews the evaluation of primary immunodeficiency diseases in children. He states when an immunodeficiency disease is suspected, initial laboratory screening should include a complete blood count with differential and measurement of serum immunoglobulin and complement levels. The presence of lymphocytopenia on complete blood count suggests a T-cell disorder, whereas a finding of neutropenia suggests a phagocytic disorder.

Boutay et al. describe the accelerated phase of CHS. They state that a majority (85%) of patients with CHS undergo an accelerated phase consisting of a lymphoproliferative syndrome with hemophagocytosis and infiltration of most tissues. This phase is characterized by fever, jaundice, hepatosplenomegaly, lymphadenopathy, pancytopenia, and neurological abnormalities.

Figure A demonstrated a patient with partial albinism due to CHS. Figure B demonstrates the giant granules that are often observed in neutrophils on the peripheral blood smear in patients with CHS.

Incorrect Answers:
Answers 1-3,5: CHS has an autosomal recessive mode of inheritance. Thus, the patterns of autosomal dominant, x-linked dominant and recessive, and maternal inheritance are not the correct mode of inheritance for CHS. Huntington disease is an example of an autosomal dominant condition, fragile X syndrome is an example of an X-linked dominant condition, hemophilia is an example of an X-linked recessive condition, and various mitochondrial hereditary diseases are examples of maternal inheritance patterns.