Netherton Syndrome with a Novel Likely Pathogenic Variant c.420del (p.Ser141ProfsTer5) in SPINK5 Gene: A Case Report

Introduction

Netherton syndrome (NS) is a rare autosomal recessive genodermatosis in the group of congenital ichthyosis. The clinical manifestations of the syndrome vary from a very mild clinical manifestation occurring with the picture of ichthyosis linearis circumflexa to exfoliative erythroderma. It can be fatal in the first days of a newborn's life due to dehydration, hypothermia, weight loss, respiratory infections, and sepsis. A specific anomaly of the hair trichorrexis invaginata is considered pathognomonic for the syndrome. Genetic testing of SPINK5 gene is key to confirming the diagnosis and starting early treatment.

Case Presentation

We present a case report of NS in a 6-year-old boy who suffered from generalized erythroderma and desquamation of the skin from birth. The patient has atopic diathesis, recurrent skin infections, increased levels of IgE, and delayed physical development. Two genetic variants in SPINK5 gene with clinical significance were identified. The first detected variant is a nonsense mutation, predicted to cause loss of normal protein function either by protein truncation or by nonsense-mediated mRNA decay. The second variant is a likely pathogenic frameshift mutation that truncates the protein in 5 amino acids. The child was treated with acitretin, without satisfactory effect.

Conclusion

The genetic variant we have described correlates with a severe clinical phenotype of NS. The second genetic variant of the SPINK5 gene, inherited from the father in our case, is novel and has never been published in the literature.

Severe Hypernatremia as Presentation of Netherton Syndrome

Netherton syndrome is a rare, multisystem, autosomal recessive genodermatosis characterized by a triad of manifestations: congenital ichthyosis, immune dysregulation, and scalp anomalies. We report the case of a 1-month-old male infant evaluated for failure to thrive and feeding difficulties. At birth, the infant was admitted to intensive care for severe hypernatremia (natremia 186 mg/dL). Upon entering the ward, the general conditions were poor. He presented with diffuse erythrodermia. A dermatological evaluation showed evidence of "invaginated trichuriasis," a typical sign of Netherton syndrome. Netherton syndrome is caused by a genetic mutation causing loss of function of the SPINK5 gene it encodes for the LEKTI protein, normally expressed in epithelia. Loss of LEKTI induces severe skin barrier defect. The history of the disease is characterized by serious potential complications in the first months of life, such as the risk of hypernatremic dehydration induced by high skin permeability, recurrent and/or severe infections, and growth retardation.

Netherton Syndrome: Case Report and Review of the Literature

Netherton syndrome (NS) is a rare genodermatosis with an autosomal recessive pattern of inheritance caused by pathogenic variants in the SPINK5 gene. It is characterized by a triad consisting of atopic diathesis, ichthyosis linearis circumflexa, and hair shaft abnormalities. Ichthyosis linearis circumflexa can be confused with atopic dermatitis leading to a delayed diagnosis. Furthermore, difficulty in making the differential diagnosis with other atopiform, erythrodermic, and ichthyosiform entities that exhibit hair shaft abnormalities represent a challenge. Trichoscopy is an accessible and noninvasive auxiliary diagnostic tool in these cases; the hair shaft abnormalities found in NS are bamboo, golf tee, and matchstick hairs. Identification of a pathogenic variant in the SPINK5 gene through genetic testing is necessary to confirm the diagnosis. Multiple treatment options are available including topical therapy with emollients, corticosteroids, calcineurin inhibitors, antiseptics, and narrowband UVB phototherapy. Systemic treatments comprehend intravenous immunoglobulins, and advances in the understanding of the pathophysiology of NS have led to more directed therapies with biologics such as infliximab, ixekizumab, secukinumab, ustekinumab, and dupilumab. Treatments currently under investigation include inhibitors of kallikrein 5, cathelicidins, drugs activating the transcription factor nuclear factor erythroid-derived 2-like 2, and gene therapy using autologous keratinocytes induced with a lentiviral vector encoding SPINK5.

Netherton's Syndrome: A Case of Two Male Siblings Diagnosed in Adulthood

Netherton's syndrome (NS) is a rare autosomal recessive genetic disease caused by a germline mutation in the SPINK5 gene. It is most commonly diagnosed in neonates due to the presence of congenital ichthyosiform erythroderma. Affected individuals will typically also develop a hair shaft abnormality known as trichorrhexis invaginata, severe atopy, and a migratory rash known as ichythyosis linearis circumflexa. The chronicity and severity of NS adversely affects a patient's quality of life to a large extent. It Is therefore important that this condition is identified early, and treatment to reduce cutaneous inflammation is initiated in a timely fashion. However, due to this condition being relatively rare, a lack of awareness may lead clinicians to misdiagnose it as atopic dermatitis or undifferentiated psoriasis. Clinicians should therefore be aware of the peripheral stigmata that this disease may present as in adulthood, so that a correct diagnosis can be made if it was previously missed. Here we present a case of two male siblings from Jordon who were misdiagnosed since childhood as having erythrodermic psoriasis. Clinical examination of one of the siblings, as an adult, revealed multiple peripheral features associated with NS. Genetic analysis through sanger sequencing was also able to identify a mutation in the SPINK5 gene, confirming the diagnosis.