Netherton综合征与SPINK5

Netheton综合征是一种严重的常染色体隐性遗传病,其预后较差死亡率高,目前尚无有效的治疗方案。研究发现,Nethetn综合征的发生可能与SPINK5突变导致的LEKTI缺陷和皮肤屏障功能障碍有关。免疫组化检测LEKTI、SPINK5基因突变分析对Netheton综合征的诊断有重要意义,胚胎植入前遗传学诊断可用于Netheton综合征的产前筛查,并有效避免患病新生儿的出生。以往对Netheton综合征的治疗以对症处理为主,随着Netheton综合征遗传学的研究进展,基因转移、局部给予LEKTI生物活性碎片和免疫球蛋白替代疗法可能是将来的发展方向。     

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.     

Correlation between SPINK5 gene mutations and clinical manifestations in Netherton syndrome patients

Netherton syndrome (NS) is a congenital ichthyosiform dermatosis caused by serine protease inhibitor Kazal-type 5 (SPINK5) mutations. Tissue kallikreins (KLKs) and lymphoepithelial Kazal-type-related inhibitor (LEKTI) (SPINK5 product) may contribute to the balance of serine proteases/inhibitors in skin and influence skin barrier function and desquamation. SPINK5 mutations, causing NS, lead to truncated LEKTI; each NS patient possesses LEKTI of a different length, depending on the location of mutations. This study aims to elucidate genotype/phenotype correlations in Japanese NS patients and to characterize the functions of each LEKTI domain. Since we were unable to demonstrate truncated proteins in tissue from patients with NS, we used recombinant protein to test the hypothesis that the length of LEKTI correlated with protease inhibitory activity. Genotype/phenotype correlations were observed with cutaneous severity, growth retardation, skin infection, stratum corneum (SC) protease activities, and KLK levels in the SC. Predominant inhibition by LEKTI domains against overall SC protease activities was trypsin-like (Phe-Ser-Arg-) activity by LEKTI domains 6-12, plasmin- and trypsin-like (Pro-Phe-Arg-) activities by domains 12-15, chymotrypsin-like activity by all domains, and furin-like activity by none. KLK levels were significantly elevated in the SC and serum of NS patients. These data link LEKTI domain deficiency and clinical manifestations in NS patients and pinpoints to possibilities for targeted therapeutic interventions.     

SPINK5 and Netherton syndrome: novel mutations, demonstration of missing LEKTI, and differential expression of transglutaminases

Netherton syndrome (NTS) is an autosomal recessive congenital ichthyosis featuring chronic inflammation of the skin, hair anomalies, epidermal hyperplasia with an impaired epidermal barrier function, failure to thrive and atopic manifestations. The disease is caused by mutations in the SPINK5 gene encoding the serine proteinase inhibitor lympho-epithelial Kazal-type inhibitor (LEKTI). Sequence analyses of SPINK5 in seven NTS patients from five different families allowed us to identify two known and three novel mutations all creating premature termination codons. We developed a monoclonal antibody giving a strong signal for LEKTI in the stratum granulosum of normal skin and demonstrated absence of the protein in NTS epidermis. Immunoblot analysis revealed presence of full length LEKTI and of LEKTI cleavage fragments in normal hair roots, whereas in NTS hair roots LEKTI and its cleavage products were completely missing. Transglutaminase1 activity was present throughout almost the entire suprabasal epidermis in NTS, whereas in normal skin it is restricted to the stratum granulosum. In contrast, immunostaining for transglutaminase3 was absent or faint. Moreover, comparable with the altered pattern in psoriatic skin the epidermis in NTS strongly expressed the serine proteinase inhibitor SKALP/elafin and the anti-microbial protein human beta-defensin 2. These studies demonstrate LEKTI deficiency in the epidermis and in hair roots at the protein level and an aberrant expression of other proteins, especially transglutaminase1 and 3, which may account for the impaired epidermal barrier in NTS.     

Netherton综合征一例SPINK5基因突变研究

目的 检测Netherton综合征患者SPINK5基因的突变情况。 方法 收集患者临床资料,提取患者及其相关亲属外周血DNA,用PCR扩增SPINK5基因编码区的全部外显子及其侧翼序列并测序。 结果 直接测序发现患者SPINK5基因的第13号外显子中的第1111位碱基发生C→T杂合突变（c.1111C > T）,导致其编码第371位氨基酸变为终止密码子（p.R371X）;第32号外显子中的第3121位碱基发生C→T杂合突变（c.3121C > T）,导致其编码第1041位氨基酸发生错义突变（p.R1041C）,其健康父母为相应突变的杂合携带者,200例健康对照未见该突变。 结论 SPINK5基因的p.R371X及p.R1041C复合杂合突变可能是引起该患者临床表现的病因之一。     

A new SPINK5 mutation in a patient with Netherton syndrome: a case report

We report on a case of Netherton syndrome showing a new SPINK5 mutation (c.957_960dupTGGT duplication in exon 11), associated with partial defect of biotinidase.     

Netherton syndrome: report of two Taiwanese siblings with staphylococcal scalded skin syndrome and mutation of SPINK5

Netherton syndrome (NS) is a severe autosomal recessive ichthyosis. It is characterized by congenital ichthyosiform erythroderma, trichorrhexis invaginata, ichthyosis linearis circumflexa, atopic diathesis and frequent bacterial infections. Pathogenic mutations in SPINK5 have recently been identified in NS. SPINK5 encodes lymphoepithelial Kazal-type-related inhibitor (LEKTI), a new type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. We report two Taiwanese brothers with NS. The patients had typical manifestations of NS with an atopic diathesis and recurrent staphylococcal infections, including staphylococcal scalded skin syndrome (SSSS) since birth. Horny layers were obtained by skin surface biopsy for electron microscopy from lesional skin of both patients and from normal controls. All 33 exons and flanking intron boundaries of SPINK5 were amplified for direct sequencing. The ultrastructure of the stratum corneum (SC) was characterized by premature degradation of corneodesmosomes (CDs) with separation of corneocytes. A homozygous 2260A --> T (K754X) mutation of SPINK5 was found in both patients. Staphylococcal exfoliative toxin A (ETA) is a serine protease capable of cleaving desmoglein 1, an important adhesive molecule of CDs, and can cause separation of the SC, resulting in SSSS. The premature degradation of CDs found in our patients may be attributable to insufficient LEKTI, and possibly also to colonization/infection of ETA-producing Staphylococcus aureus. Mechanisms involved in the pathogenesis of the skin barrier defect in NS are proposed. Further study is needed to prove this hypothesis.     

Deleterious mutations in SPINK5 in a patient with congenital ichthyosiform erythroderma: molecular testing as a helpful diagnostic tool for Netherton syndrome

The congenital erythrodermas represent a heterogeneous group of inherited and acquired disorders often accompanied by systemic infections, impaired epidermal barrier function and concomitant life-threatening fluid and electrolyte imbalance. In the present report, we describe a patient who was considered to have congenital ichthyosiform erythroderma for 26 years until molecular testing led to the correct diagnosis of Netherton syndrome.     

A novel SPINK5 mutation and successful subcutaneous immunoglobulin replacement therapy in a child with Netherton syndrome

We report a 2-year-old patient with Netherton syndrome presenting with generalized exfoliative erythroderma, ichthyosiform dermatitis, trichorrhexis invaginata, hypernatremic dehydration, failure to thrive, and recurrent respiratory infections. Molecular analysis of SPINK5 identified a novel mutation (c.1530CA). Our case report also verifies and supports the safety and efficacy of subcutaneous immunoglobulin substitution in chronic generalized skin disorders associated with primary immunodeficiencies such as Netherton syndrome.     

Netherton syndrome: mutation analysis of two Taiwanese families

Netherton syndrome (NS) is a severe autosomal recessive skin disorder characterized by congenital ichthyosiform erythroderma, hair shaft abnormalities, and atopic diathesis. Recently, pathogenic mutations were identified in serine protease inhibitor Kazal-type 5 (SPINK5), the gene that encodes lympho-epithelial Kazal-type related inhibitor (LEKTI), a type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. In the present report, we describe the mutation analysis of two Taiwanese patients with NS. Patient 1 has heterozygous mutations; the maternal allele has novel T808I (C–T transition in codon 808) and the paternal allele has recurrent R790X (C–T transition in codon 790). Patient 2 is homozygous for a novel polymorphism R267Q (G–A transition in codon 267). The change was not detected in the patient’s father. Haplotype analysis revealed that the patient was homozygous for the 5 single nucleotide polymorphisms in the genomic sequence of SPINK5 as well as the flanking (GT)₁₇ and D5S413, in addition to the discrepancy of R267Q. Nevertheless real-time quantitative PCR analysis revealed no microdeletion in the genomic sequence of SPINK5. Thus uniparental disomy of maternal SPINK5 allele was indicated. Shuan-Pei Lin and Shu-Yi Huang contributed equally to this work.     

Netherton syndrome with extensive skin peeling and failure to thrive due to a homozygous frameshift mutation in SPINK5

BACKGROUND: Netherton syndrome (NTS) is a rare autosomal recessive multisystem disorder characterized by congenital erythroderma and ichthyosis, hair shaft abnormalities and immune dysregulation. The disorder is caused by deleterious mutations in the SPINK5 gene, encoding the serine protease inhibitor LEKTI. OBJECTIVE: Our objective was to investigate if the erythrodermic variant of peeling skin syndrome is also caused by SPINK5 mutations and to study the consequences of the disease on infantile brain development. METHODS: In an infant with extensive erythroderma, peeling skin and failure to thrive, we analyzed the SPINK5 gene for pathogenic mutations by direct DNA sequencing and performed repeated brain MRI studies with diffusion-weighted imaging. RESULTS: We identified a homozygous 4-base-pair insertion in exon 5 of SPINK5, which introduces a premature termination codon and appears to be a common mutation among West Indies islanders. MRI analyses revealed a persistent diffuse volume loss. CONCLUSION: Our results confirm that early truncation mutations of the coding sequence of SPINK5 produce a severe phenotype and that generalized peeling skin is one of the manifestations of NTS. We further demonstrate for the first time that NTS may be associated with MRI abnormalities indicative of a permanent tissue injury of the brain.     

Netherton syndrome in one Chinese adult with a novel mutation in the SPINK5 gene and immunohistochemical studies of LEKTI

Background:

Netherton syndrome (NS) is a severe autosomal recessive ichthyosis. It is characterized by congenital ichthyosiform erythroderma, trichorrhexis invaginata, ichthyosis linearis circumflexa, atopic diathesis, and frequent bacterial infections. The disease is caused by mutations in the SPINK5 (serine protease inhibitor Kazal-type 5) gene, a new type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. We report one Chinese adult with NS. The patient had typical manifestation of NS except for trichorrhexis invaginata with an atopic diathesis and recurrent staphylococcal infections since birth.

Aims:

To evaluate the gene mutation and of its product activity of SPINK5 gene in confirmation of the diagnosis of one Chinese adult with NS.

Materials and Methods:

To screen mutations in the SPINK5 gene, 33 exons and flanking intron boundaries of SPINK5 were amplified with polymerase chain reaction (PCR) and used for direct sequencing. In addition, immunohistochemical staining of LEKTI (lymphoepithelial Kazal-type-related inhibitor) with specific antibody was used to confirm the diagnosis of NS. The results were compared with that of healthy individuals (twenty-five blood samples).

Results:

A G318A mutation was found at exon 5 of patient''s SPINK5 gene which is a novel missense mutation. The PCR amplification products with mutation-specific primer were obtained only from the DNA of the patients and their mother, but not from their father and 25 healthy individuals. Immunohistochemical studies indicated there was no LEKTI expression in NS patient''s skin and there was a strong LEKTI expression in the normal human skin.

Conclusion:

In this report, we describe heterozygous mutation in the SPINK5 gene and expression of LEKTI in one Chinese with NS. The results indicate that defective expression of LEKTI in the epidermis and mutations of SPINK5 gene are reliable for diagnostic feature of NS with atypical clinical symptoms.     

两个Netherton综合征家系SPINK5基因突变及产物活性的检测

目的研究两个Netherton综合征家系的SPINK5基因突变及产物活性情况。方法采用免疫组化法检测SPINK5基因编码的LEKTI在表皮中的活性,用聚合酶链反应-DNA直接测序法检测基因突变。结果患者均有LEKTI的活性降低。一个家系先证者有SPINK5基因1430+2 T>G的纯合性突变。其母亲为该突变的杂合子,表型正常。另一个家系未发现突变。结论两个家系患者均有LEKTI的活性降低,第一个家系的先证者存在SPINK5基因1430+2 T>G纯合性的剪切突变。     

New homozygous SPINK5 mutation, p.Gln333X, in a Turkish pedigree with Netherton syndrome

Netherton syndrome (NS) is a rare autosomal recessive genodermatosis caused by loss-of-function mutations in the SPINK5 gene. The clinical features include congenital ichthyosis, trichorrhexis invaginata and atopy. In this study, we report a new homozygous SPINK5 mutation, p.Gln333X, responsible for NS in affected members of two closely related Turkish families, and provide an overview of the genotype-phenotype correlation in this condition.     

Netherton syndrome in two Japanese siblings with a novel mutation in the SPINK5 gene: immunohistochemical studies of LEKTI and other epidermal molecules

BACKGROUND: Netherton syndrome (NS) is a severe autosomal recessive disorder characterized by ichthyosiform erythroderma, bamboo hair and atopy. The disease is caused by mutations in the SPINK5 gene, which encodes a putative serine protease inhibitor, LEKTI (lymphoepithelial Kazal-type-related inhibitor). Previous studies have clearly shown a crucial role for LEKTI in skin barrier formation. OBJECTIVES: To identify pathogenic mutations in two Japanese siblings with NS, and further to investigate the consequences of the mutations at the protein level. METHODS: To screen for mutations in the SPINK5 gene, all of its exons and splice junctions were amplified by polymerase chain reaction and directly sequenced. In addition, immunohistochemical staining of LEKTI, desmoglein (Dsg) 1 and elafin was performed with their specific antibodies. RESULTS: Mutation analysis resulted in the identification of compound heterozygous mutations, Q713X and R790X, in the SPINK5 gene of both patients. The former one is a novel mutation. Immunohistochemical studies in one patient demonstrated a complete absence of LEKTI and a strong expression of elafin in the patient's skin. Dsg1 was normally expressed in our patient. CONCLUSIONS: In this report, we describe compound heterozygous mutations in the SPINK5 gene in two Japanese siblings with NS. The result of immunohistochemistry shows LEKTI deficiency and upregulation of elafin in the skin of one patient. Furthermore, our data indicate that degradation of Dsg1 does not always occur in NS.     

Lethal Netherton Syndrome Due to Homozygous p.Arg371X Mutation in SPINK5

Here we report a lethal case of Netherton syndrome presenting with neurologic complications, hypernatremic dehydration, failure to thrive, and episodes of sepsis. Molecular analysis of the serine protease inhibitor Kazal‐type 5 gene identified a homozygous mutation (c.1111C>T, p.Arg371X). This case highlights the importance of early diagnosis to start appropriate care in a timely fashion and prevent disease complications.     

SPINK5 knockdown in organotypic human skin culture as a model system for Netherton syndrome: effect of genetic inhibition of serine proteases kallikrein 5 and kallikrein 7

Netherton syndrome (NS; OMIM 256500) is a genetic skin disease resulting from defects in the serine protease inhibitor Kazal‐type 5 (SPINK5) gene, which encodes the protease inhibitor lympho‐epithelial Kazal type inhibitor (LEKTI). We established a SPINK5 knockdown skin model by transfecting SPINK5 small interfering RNA (siRNA) into normal human epidermal keratinocytes, which were used together with fibroblast‐populated collagen gels to generate organotypic skin cultures. This model recapitulates some of the NS skin morphology: thicker, parakeratotic stratum corneum frequently detached from the underlying epidermis and loss of corneodesmosomes. As enhanced serine protease activity has been implicated in the disease pathogenesis, we investigated the impact of the kallikreins KLK5 [stratum corneum trypsin‐like enzyme (SCTE)] and KLK7 [stratum corneum chymotrypsin‐like enzyme (SCCE)] on the SPINK5 knockdown phenotype by generating double knockdowns in the organotypic model. Knockdown of KLK5 or KLK7 partially ameliorated the epidermal architecture: increased epidermal thickness and expression of desmocollin 1 (DSC1), desmoglein 1 (DSG1) and (pro)filaggrin. Thus, inhibition of serine proteases KLK5 and KLK7 could be therapeutically beneficial in NS.