Insights into Mutation Effect in Three Poikiloderma with Neutropenia Patients by Transcript Analysis and Disease Evolution of Reported Patients with the Same Pathogenic Variants

From clinical findings to the pathomechanism of poikiloderma with neutropenia

The clinical problem of a non-healing fistula in ano in a child affected with poikiloderma with neutropenia (PN) was the stimulus for an innovative study by Parajuli et al. that sheds light on the pathological mechanisms in this disease. Multiparametric analyses of the patient's blood mononuclear cells by cell culture, flow cytometry and multiplex cytokine assay suggested a block of monocyte differentiation. Monocyte transcriptome profiling revealed a signature consistent with the haematological picture and the clinical presentation. Commentary on: Parajuli et al. Defective monocyte plasticity and altered cAMP pathway characterize USB1-mutated poikiloderma with neutropenia Clericuzio type. Br J Haematol 2024;204:683-693.

Poikiloderma With Neutropenia and Mastocytosis: A Case Report and a Review of Dermatological Signs

Poikiloderma with neutropenia (PN) is a very rare genetic disorder mainly characterized by poikiloderma and congenital neutropenia, which explains the recurrence of respiratory infections and risk of developing bronchiectasis. Patients are also prone to develop hematological and skin cancers. Here, we present the case of a patient, the only child of apparently unrelated Serbian parents, affected by PN resulting from the homozygous mutation NM_024598.3:c.243G>A (p.Trp81Ter) of USB1; early onset of poikiloderma (1 year of age) was associated with cutaneous mastocytosis. We also provide a review of the literature on this uncommon condition with a focus on dermatological findings.

Poikiloderma with Neutropenia, Clericuzio-Type Accompanied by Loss of Digits Due to Severe Osteomyelitis

Poikiloderma with neutropenia (PN), Clericuzio-type is a rare autosomal recessively transmitted genodermatosis caused by biallelic mutations in the USB1 gene and is characterized by early-onset poikiloderma and chronic neutropenia. Nail dystrophy, palmoplantar hyperkeratosis, hypogonadotropic hypogonadism, and recurrent infections can be associated with the disease. Herein, we present a 27-year-old Turkish male patient newly diagnosed as PN, Clericuzio-type after confirmation of a c.531delA (p.His179MetfsX86) homozygous deleterious mutation in exon 5 of the USB1 gene. The presented case highlights the importance of genetic testing for avoiding misdiagnosis based solely on clinical findings, as well as the benefit of a multi-disciplinary diagnostic approach, as he was initially misdiagnosed as Rothmund-Thompson syndrome and subsequently diagnosed as PN, Clericuzio-type at age 27 years.