Kostmann Disease Workup

Updated: Aug 24, 2017
  • Author: Peter N Huynh, MD; Chief Editor: Harumi Jyonouchi, MD  more...
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Workup

Laboratory Studies

An absolute neutrophil count (ANC) of less than 200/μL is seen in classic cases of severe congenital neutropenia (see the Absolute Neutrophil Count calculator).

Monocytosis and eosinophilia may be evident. Total leukocyte counts are frequently normal because of the monocytosis. Mild anemia may be present from chronic inflammation, and thrombocytosis may be present.

Quantitative immunoglobulins may show hypergammaglobulinemia. Patients have a normal response to vaccinations.

Complement levels typically are normal.

Antineutrophil antibodies are absent but should be checked to exclude an autoimmune etiology when the diagnosis is entertained in the first few months of life.

Electrolyte levels and renal and liver function test results are within the normal range.

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Imaging Studies

Imaging studies are performed only as clinically indicated to evaluate for infection. Bone density (duel-energy x-ray absorptiometry [DEXA] scanning) is performed to evaluate for osteopenia or osteoporosis.

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Other Tests

Genetic testing can be considered to differentiate between the variants of severe congenital neutropenia depending on the clinical findings.

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Procedures

Bone marrow biopsy can be very helpful in the diagnosis of severe congenital neutropenia. Bone marrow is also necessary to rule out malignant conditions, evaluate myeloid maturation, determine cellularity, and elucidate an etiology. [15]

When leukemic or myelodysplastic transformation occurs, bone marrow cytogenetics exhibit monosomy 7 in 50% of cases. Granulocyte colony-stimulating factor (G-CSF) receptor mutations occur within an intracellular part of the receptor and can be identified from either blood or bone marrow samples. As G-CSF receptor mutations (CSF3R) are not present at birth, they do not represent the underlying defect for the disease.

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Histologic Findings

The bone marrow findings of severe congenital neutropenia typically demonstrate normal or decreased cellularity with an arrest of neutrophil precursor maturation at the promyelocyte or myelocyte level. This is typically seen in the severe congenital neutropenia due to ELANE, HAX1, WASp, G6PC3, and CSF3R mutations. Maturation arrest in the promyelocyte phase is often associated with bone marrow hypereosinophilia and monocytosis. [15]

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