The packet lists one gene, USB1 (chromosome 16), for this condition. No ClinGen validity classification is supplied in the packet. GeneReviews describes the condition as inherited in an autosomal recessive manner, and the packet's inheritance field is AUTOSOMAL_RECESSIVE. According to GeneReviews, parents of an affected child are presumed to be heterozygous for a USB1 pathogenic variant, and heterozygous carriers are described as asymptomatic and not at risk of developing the disorder. When both parents are known to be heterozygous, GeneReviews gives each sibling of an affected individual a 25% chance at conception of being affected, a 50% chance of being an asymptomatic carrier and a 25% chance of being unaffected and not a carrier. GeneReviews notes that a variant found in only one parent may reflect a de novo event in the proband or a postzygotic de novo event in a mosaic parent. Family history is described as consistent with autosomal recessive inheritance, for example affected siblings or parental consanguinity; this is more likely when parents share a common ancestor, since both would then be more likely to carry the same rare variant. GeneReviews notes that one USB1 variant has been identified in 22 individuals from 16 families of Turkish ancestry and is the most prevalent USB1 pathogenic variant identified to date.

GeneReviews states that the clinical diagnosis can be established in a proband with post-inflammatory poikiloderma and congenital chronic neutropenia, or the molecular diagnosis can be established in a proband with biallelic pathogenic or likely pathogenic variants in USB1. Suggestive findings described by GeneReviews include the infant rash followed by poikiloderma after age two years, recurrent sinopulmonary infections in the first two years of life, adolescent- and adult-onset non-healing skin ulcers, cellulitis and osteomyelitis. Laboratory findings are described as congenital chronic noncyclic neutropenia that is moderate (absolute neutrophil count of 500-1,000/microliter) to severe.

Molecular approaches named by GeneReviews include single-gene sequence analysis of USB1, followed by deletion/duplication analysis if one or no variant is found, multigene panels that include USB1, and comprehensive genomic testing such as exome or genome sequencing. GeneReviews adds that biallelic variants of uncertain significance do not establish or rule out the diagnosis. Before USB1 molecular testing, individuals with PN were clinically misdiagnosed as having Rothmund-Thomson syndrome, dyskeratosis congenita and Kindler syndrome, according to GeneReviews.

The packet supplies no approved-treatment or orphan-drug records for this condition, so no FDA-approved option is certified here. GeneReviews management content describes supportive care, ideally delivered through multidisciplinary specialist care, aimed at quality of life, function and complications. For skin manifestations, GeneReviews lists bland emollients, sunscreens and sun-protective clothing, topical steroids for keratosis-associated discomfort and topical keratolytics for hyperkeratosis. Gingivitis and dental caries are addressed through dental cleaning with treatment per dentist.

For neutropenia, GeneReviews states that no reports have indicated definitive benefit of G-CSF and that its use is considered only in persons with severe infections and very low neutrophil counts. For sinopulmonary, middle ear and skin infections, GeneReviews lists antibiotic treatment until clinical resolution, influenza vaccination and, from the authors' personal observation, prophylactic antibiotics during winter. It states there is no rationale for immunoglobulin therapy in the absence of low immunoglobulin levels. Reactive airway disease is managed per pulmonologist. Premyelodysplastic changes are managed per hematologist/oncologist. For growth deficiency GeneReviews states there is no known treatment and no evidence that growth hormone improves linear growth. Management of hypogonadotropic hypogonadism per endocrinologist and developmental support are also described.

GeneReviews also describes surveillance across systems, covering physician examination, skin assessment including dermatologic skin cancer examination, dental evaluation, pulmonary evaluation, blood counts for signs of myelodysplastic syndrome, growth and pubertal assessment in childhood, bone density assessment in adults, and developmental assessment.

The packet does not include a certified natural history statement or survival information. GeneReviews describes persistent poikiloderma throughout life, an increased risk of myelodysplastic syndrome that may evolve into acute myelogenous leukemia, and the observation that after age five to ten years the frequency of acute sinopulmonary infections decreases while most individuals continue to have bronchiectasis, chronic non-productive cough and reactive airway disease. Intrafamilial variability is described, including acute myelogenous leukemia in one of two siblings. Life expectancy is not certified in this packet.

The packet's clinical-trial records are not certified as relating to this condition. The ten detailed records supplied have titles referring to Prurigo Nodularis, a term that appears among the packet's synonyms but is not described as this condition, and none is linked in the packet to poikiloderma with neutropenia. No trial activity is therefore described for this condition.