Cartilage-hair hypoplasia-anauxetic dysplasia spectrum disorders harboring RMRP mutations in two Korean children: A case report.

RATIONALE: Cartilage-hair hypoplasia (CHH, OMIM # 250250) is a rare autosomal recessive disorder, which includes cartilage-hair hypoplasia-anauxetic dysplasia (CHH-AD) spectrum disorders. CHH-AD is caused by homozygous or compound heterozygous mutations in the RNA component of the mitochondrial RNA-processing Endoribonuclease (RMRP) gene. PATIENT CONCERNS: Here, we report 2 cases of Korean children with CHH-AD. DIAGNOSES: In the first case, the patient had metaphyseal dysplasia without hypotrichosis, diagnosed by whole exome sequencing (WES), and exhibited only skeletal dysplasia and lacked extraskeletal manifestations, such as hair hypoplasia and immunodeficiency. In the second case, the patient had skeletal dysplasia, hair hypoplasia, and immunodeficiency, which were identified by WES. INTERVENTIONS: The second case is the first CHH reported in Korea. The patients in both cases received regular immune and lung function checkups. OUTCOMES: Our cases suggest that children with extremely short stature from birth, with or without extraskeletal manifestations, should include CHH-AD as a differential diagnosis. LESSONS SUBSECTIONS: Clinical suspicion is the most important and RMRP sequencing should be considered for the diagnosis of CHH-AD.

Extensive and deep granulomatous ulcers as an atypical manifestation of cartilage-hair hypoplasia syndrome: A diagnostic and therapeutic challenge.

Cartilage hypoplasia syndrome is a primary immunodeficiency disease characterized by short stature, hypoplastic hair and a variable degree of immunodeficiency. Noninfectious cutaneous granulomas represent an uncommon yet well-recognized manifestation within the spectrum of primary immunodeficiency diseases. However, cutaneous granulomas as a manifestation of cartilage-hair hypoplasia syndrome, are extremely rare. We present a case of a middle-aged man with cartilage hypoplasia syndrome featuring cutaneous granulomas, manifesting as chronic, extensive and deep cutaneous ulcers. The patient was treated with anti-TNF-alpha adalimumab with partial improvement. Our case underscores the broad spectrum of clinical manifestations associated with cartilage hypoplasia syndrome and adds new evidence to the potential therapeutic efficacy of anti-TNF-alpha drugs in its treatment.

[Bazex syndrome: a rare paraneoplastic disease]. / Síndrome de Bazex: una enfermedad paraneoplásica infrecuente.

Bazex syndrome is a paraneoplastic disorder most commonly linked to squamous cell carcinomas of the upper aerodigestive tract, followed by lung cancer and other malignancies. It manifests through three stages of skin involvement that mirror the tumor's progression. Remarkably, skin lesions precede tumor symptoms or diagnosis in two-thirds of cases, underscoring the crucial role of suspecting this condition as it can promptly reveal an underlying neoplasm. Treatment primarily focuses on addressing the root neoplasm, with recurrent skin lesions potentially indicating tumor relapse. In this context, we present a clinical case involving a male patient whose manifestation of this syndrome facilitated the timely diagnosis of lung adenocarcinoma. This case underscores the significance of understanding this uncommon syndrome and its link to cancer, enabling early and accurate oncological diagnosis.

El síndrome de Bazex es una enfermedad paraneoplásica que se asocia con mayor frecuencia a carcinomas de células escamosas del tracto aerodigestivo superior, seguido en frecuencia por el cáncer de pulmón y otras neoplasias. Afecta a la piel en tres etapas que tienen un comportamiento paralelo al crecimiento del tumor. En dos tercios de los casos, las lesiones cutáneas preceden a los síntomas o al diagnóstico del tumor. De ahí la importancia de la sospecha de esta entidad, que puede desenmascarar a la neoplasia asociada en una etapa temprana. Su tratamiento consiste en tratar la neoplasia subyacente. La recurrencia de las lesiones cutáneas puede revelar la recaída del tumor. Comunicamos el caso clínico de un paciente de sexo masculino en el cual el hallazgo de este síndrome permitió realizar el diagnóstico de un adenocarcinoma de pulmón, lo cual destaca la importancia de conocer a esta rara enfermedad y su asociación con cáncer, para poder realizar el diagnóstico oncológico de forma temprana y oportuna.

Increased Hemichannel Activity Displayed by a Connexin43 Mutation Causing a Familial Connexinopathy Exhibiting Hypotrichosis with Follicular Keratosis and Hyperostosis.

Mutations in the GJA1 gene that encodes connexin43 (Cx43) cause several rare genetic disorders, including diseases affecting the epidermis. Here, we examined the in vitro functional consequences of a Cx43 mutation, Cx43-G38E, linked to a novel human phenotype of hypotrichosis, follicular keratosis and hyperostosis. We found that Cx43-G38E was efficiently translated in Xenopus oocytes and localized to gap junction plaques in transfected HeLa cells. Cx43-G38E formed functional gap junction channels with the same efficiency as wild-type Cx43 in Xenopus oocytes, although voltage gating of the gap junction channels was altered. Notably, Cx43-G38E significantly increased membrane current flow through the formation of active hemichannels when compared to wild-type Cx43. These data demonstrate the association of increased hemichannel activity to a connexin mutation linked to a skeletal-cutaneous phenotype, suggesting that augmented hemichannel activity could play a role in skin and skeletal disorders caused by human Cx43 mutations.

Novel blended SNRPE-related spliceosomopathy phenotype characterized by microcephaly and congenital atrichia.

Variants in genes encoding core components of the spliceosomes are associated with craniofacial syndromes, collectively called craniofacial spliceosomopathies. SNRPE encodes a core component of pre-mRNA processing U-rich small nuclear ribonuclear proteins (UsnRNPs). Heterozygous variants in SNRPE have been reported in six families with isolated hypotrichosis simplex in addition to one case of isolated non syndromic congenital microcephaly. Here, we report a patient with a novel blended phenotype of microcephaly and congenital atrichia with multiple congenital anomalies due to a de novo intronic SNRPE deletion, c.82-28_82-16del, which results in exon skipping. As discussed within, this phenotype, which we propose be named SNRPE-related syndromic microcephaly and hypotrichosis, overlaps other craniofacial splicesosomopathies.

Biallelic mutations in LSS in autosomal-recessive mutilating palmoplantar keratoderma.

Mutilating palmoplantar keratoderma (PPK) is a heterogeneous genetic disease that poses enormous challenges to clinical diagnosis and genetic counselling. Lanosterol synthase (LSS) gene encodes LSS involved in the biosynthesis pathway of cholesterol. Biallelic mutations in LSS were found to be related to diseases such as cataracts, hypotrichosis and palmoplantar keratoderma-congenital alopecia syndrome. The aim of this study was to investigate the contribution of the LSS mutation to mutilating PPK in a Chinese patient. The clinical and molecular characteristics of the patient were evaluated. A 38-year-old male patient with mutilating PPK was recruited in this study. We identified biallelic variants in the LSS gene (c.683C > T, p.Thr228Ile and c.779G > A, p.Arg260His). Immunoblotting revealed that the Arg260His mutant showed a significantly reduced expression level while Thr228Ile showed an expression level similar to that of the wild type. Thin layer chromatography revealed that mutant Thr228Ile retained partial enzymatic activity and mutant Arg260His did not show any catalytic activity. Our findings show the correlation between LSS mutations and mutilating PPK.

Loss-of-function mutations in CST6 cause dry skin, desquamation and abnormal keratosis without hypotrichosis.

Cystatin M/E (encoded by the CST6 gene) is a cysteine protease inhibitor, that exerts regulatory and protective effects against uncontrolled proteolysis mainly by directly regulating cathepsin V, cathepsin L, and legumain activities. Previous studies have suggested that CST6 may exert a regulatory role in epidermal differentiation and hair follicle formation by inhibiting the activity of respective cognate target proteases. However, until recently, studies have revealed that loss- or gain-of-function of the CST6 gene causes dry skin with hypotrichosis in humans. Here, we reported two siblings of Chinese origin with dry skin, desquamation and abnormal keratosis without hypotrichosis. By applying whole-exome sequencing, we identified homozygous loss-of-function mutation c.251G > A (p.Gly84Asp) in the CST6 gene as the underlying genetic cause. Further fluorimetric enzyme assays demonstrated the mutant cystatin M/E protein lost its inhibitory function on the protease activity of cathepsins. Moreover, the corresponding mutation in mice resulted in excessive cornification, desquamation, impaired skin barrier function, and abnormal proliferation and differentiation of keratinocytes. In conclusion, the homozygous missense mutation c.251G > A in CST6 gene resulted in dry skin, desquamation, as well as abnormal keratosis of the skin, promoting our understanding of the role of protease-antiprotease balance in human skin disorders.

A Missense Mutation in the Collagen Triple Helix of EDA Is Associated with X-Linked Recessive Hypohidrotic Ectodermal Dysplasia in Fleckvieh Cattle.

Mutations within the ectodysplasin A (EDA) gene have been associated with congenital hypotrichosis and anodontia (HAD/XHED) in humans, mice, dogs and cattle. We identified a three-generation family of Fleckvieh cattle with male calves exhibiting clinical and histopathological signs consistent with an X-linked recessive HAD (XHED). Whole genome and Sanger sequencing of cDNA showed a perfect association of the missense mutation g.85716041G>A (ss2019497443, rs1114816375) within the EDA gene with all three cases following an X-linked recessive inheritance, but normal EDAR and EDARADD. This mutation causes an exchange of glycine (G) with arginine (R) at amino acid position 227 (p.227G>R) in the second collagen triple helix repeat domain of EDA. The EDA variant was associated with a significant reduction and underdevelopment of hair follicles along with a reduced outgrowth of hairs, a complete loss of seromucous nasolabial and mucous tracheal and bronchial glands and a malformation of and reduction in number of teeth. Thermostability of EDA G227R was reduced, consistent with a relatively mild hair and tooth phenotype. However, incisors and canines were more severely affected in one of the calves, which correlated with the presence of a homozygous missense mutation of RNF111 (g.51306765T>G), a putative candidate gene possibly associated with tooth number in EDA-deficient Fleckvieh calves.

Germline intergenic duplications at Xq26.1 underlie Bazex-Dupré-Christol basal cell carcinoma susceptibility syndrome.

BACKGROUND: Bazex-Dupré-Christol syndrome (BDCS; MIM301845) is a rare X-linked dominant genodermatosis characterized by follicular atrophoderma, congenital hypotrichosis and multiple basal cell carcinomas (BCCs). Previous studies have linked BDCS to an 11·4-Mb interval on chromosome Xq25-q27.1. However, the genetic mechanism of BDCS remains an open question. OBJECTIVES: To investigate the genetic aetiology and molecular mechanisms underlying BDCS. METHODS: We ascertained multiple individuals from eight unrelated families affected with BDCS (F1-F8). Whole-exome (F1 and F2) and genome sequencing (F3) were performed to identify putative disease-causing variants within the linkage region. Array comparative genomic hybridization and quantitative polymerase chain reaction (PCR) were used to explore copy number variations, followed by long-range gap PCR and Sanger sequencing to amplify the duplication junctions and to define the head-tail junctions. Hi-C was performed on dermal fibroblasts from two affected individuals with BDCS and one control. Public datasets and tools were used to identify regulatory elements and transcription factor binding sites within the minimal duplicated region. Immunofluorescence was performed in hair follicles, BCCs and trichoepitheliomas from patients with BDCS and sporadic BCCs. The ACTRT1 variant c.547dup (p.Met183Asnfs*17), previously proposed to cause BDCS, was evaluated with t allele frequency calculator. RESULTS: In eight families with BDCS, we identified overlapping 18-135-kb duplications (six inherited and two de novo) at Xq26.1, flanked by ARHGAP36 and IGSF1. Hi-C showed that the duplications did not affect the topologically associated domain, but may alter the interactions between flanking genes and putative enhancers located in the minimal duplicated region. We detected ARHGAP36 expression near the control hair follicular stem cell compartment, and found increased ARHGAP36 levels in hair follicles in telogen, in BCCs and in trichoepitheliomas from patients with BDCS. ARHGAP36 was also detected in sporadic BCCs from individuals without BDCS. Our modelling showed the predicted maximum tolerated minor allele frequency of ACTRT1 variants in control populations to be orders of magnitude higher than expected for a high-penetrant ultra-rare disorder, suggesting loss of function of ACTRT1 variants to be an unlikely cause for BDCS. CONCLUSIONS: Noncoding Xq26.1 duplications cause BDCS. The BDCS duplications most likely lead to dysregulation of ARHGAP36. ARHGAP36 is a potential therapeutic target for both inherited and sporadic BCCs. What is already known about this topic? Bazex-Dupré-Christol syndrome (BDCS) is a rare X-linked basal cell carcinoma susceptibility syndrome linked to an 11·4-Mb interval on chromosome Xq25-q27.1. Loss-of-function variants in ACTRT1 and its regulatory elements were suggested to cause BDCS. What does this study add? BDCS is caused by small tandem noncoding intergenic duplications at chromosome Xq26.1. The Xq26.1 BDCS duplications likely dysregulate ARHGAP36, the flanking centromeric gene. ACTRT1 loss-of-function variants are unlikely to cause BDCS. What is the translational message? This study provides the basis for accurate genetic testing for BDCS, which will aid precise diagnosis and appropriate surveillance and clinical management. ARHGAP36 may be a novel therapeutic target for all forms of sporadic basal cell carcinomas.

Ten-year follow-up of Nicolaides-Baraitser syndrome with a de novo mutation and analysis of 58 gene loci of SMARCA2-associated NCBRS.

As a clinical subtype of SWI/SNF-related intellectual disability syndromes, Nicolaides-Baraitser syndrome (NCBRS, OMIM601358) has a unique genotype-phenotype. Due to the scarcity of the number of cases reported and the limitations of diagnosis methods, so far only more than 80 cases have been reported worldwide. In this article, a new patient with a de novo mutation was followed up for 10 years; it includes the epilepsy treatment process, the characteristics of NBCRS with seizures, typical faces, sparse hair, prominent interphalangeal joints, and intellectual disability, and we also summarized the genotype-phenotype of the 80 reported cases for comparison. Due to insufficient studies and lack of attention paid to the syndrome, it is believed that the actual number of cases should be far more than the reported number. The syndrome is phased and progressive. The genotype-phenotype correlation of the disease is related to the location of the gene locus, especially closely related to the SNF2 ATPase domain. CONCLUSIONS: The understanding of NCBRS is lagging, we need to strengthen the screening process of the phenotypic disease with intellectual disability, and perfecting multiple types of diagnostic techniques will help the discovery of the disease; its clinical features are staged and are slowly progressive, and long-term prognosis must be taken precautious with long-term follow-up required.

The first reported case of CDH3-related hypotrichosis with juvenile macular dystrophy from Jordan: a case report.

BACKGROUND: Pathogenic variants in the Cadherin 3 (CDH3) gene are responsible for the occurrence of Hypotrichosis with Juvenile Macular Dystrophy (HJMD) and Ectodermal Dysplasia, Ectrodactyly and Macular Dystrophy Syndrome (EEMS), both of which are rare autosomal recessive disorders characterized by hypotrichosis and progressive macular dystrophy. The CDH3 gene encodes for P-cadherin, a calcium-binding protein that is essential for cell-cell adhesion, which is expressed in the retinal pigment epithelial cells and hair follicles. MATERIALS AND METHODS: Fundus examination of both eyes was done in addition to clinical investigation. Genomic DNA was extracted from a whole-blood sample and whole-exome sequencing (WES) was performed to identify the underlying etiology.All identified variants were evaluated for their pathogenicity and causality. RESULTS: We present the first case of HJMD in a 23-year-old female patient from Jordan. The patient presented to our ophthalmology clinic with poor vision in both eyes. Gross examination revealed sparse scalp hair along with macular dystrophy on fundus exam in both eyes. HJMD was suspected and whole-exome sequencing (WES) confirmed the diagnosis with the identification of a homozygous frameshift deletion (p.Gly277AlafsTer20) localised in exon 7 of the CDH3 gene. CONCLUSION: Blindness due to progressive macular degeneration is a common manifestation in numerous syndromic recessive disorders such as HJMD. Ophthalmologists should consider the importance of systemic manifestations and genetic testing for the confirmation of diagnosis.

Update of recent findings in genetic hair disorders.

Genetic hair disorders, although unusual, are not very rare, and dermatologists often have opportunities to see patients. Significant advances in molecular genetics have led to identifying many causative genes for genetic hair disorders, including the recently identified causative genes, such as LSS and C3ORF52. Many patients have been detected with autosomal recessive woolly hair/hypotrichosis in the Japanese population caused by founder mutations in the LIPH gene. Additionally, many patients with genetic hair disorders caused by other genes have been reported in East Asia including Japan. Understanding genetic hair disorders is essential for dermatologists, and the findings obtained from analyzing these diseases will contribute to revealing the mechanisms of hair follicle morphogenesis and development in humans.

Simulated patients and their reality: An inquiry into theory and method.

Simulated standardized patients (SSP) have emerged as close to a 'gold standard' for measuring the quality of clinical care. This method resolves problems of patient mix across healthcare providers and allows care to be benchmarked against preexisting standards. Nevertheless, SSPs are not real patients. How, then, should data from SSPs be considered relative to clinical observations with 'real' patients in a given health system? Here, we reject the proposition that SSPs are direct substitutes for real patients and that the validity of SSP studies therefore relies on their ability to imitate real patients. Instead, we argue that the success of the SSP methodology lies in its counterfactual manipulations of the possibilities available to real careseekers - especially those paths not taken up by them - through which real responses can be elicited from real providers. Using results from a unique pilot study where SSPs returned to providers for follow-ups when asked, we demonstrate that the SSP method works well to elicit responses from the provider through conditional manipulations of SSP behavior. At the same time, observational methods are better suited to understand what choices real people make, and how these can affect the direction of diagnosis and treatment. A combination of SSP and observational methods can thus help parse out how quality of care emerges for the "patient" as a shared history between care-seeking individuals and care providers.

Estudo exploratório da Síndrome Hipoplasia Cartilagem-Cabelo no Brasil: uma abordagem genômica, proteômica e de análise estrutural de RNA / Exploratory study of Hypoplastic Cartilage-Hair Syndrome in Brazil: a genomic, proteomic and RNA structural analysis approach

A Hipoplasia Cartilagem-Cabelo (do inglês, Cartilage Hair Hypoplasia; CHH) é uma doença autossômica recessiva descrita por McKusick et al., em 1964 em crianças da comunidade Amish. Clinicamente, os pacientes apresentam displasia óssea metafisária em diferentes graus de gravidade. Além disso, também pode ser observado hipotricose e imunodeficiência. Já no âmbito molecular, a condição se caracteriza por variantes patogênicas do gene RMRP. Apesar de ter sido delineada há quase 60 anos, ainda não existe uma correlação genótipo-fenótipo bem compreendida. Este trabalho é uma continuação do trabalho de mestrado realizado no IFF/Fiocruz, durante 2017 e 2018, no qual foi descrita uma coorte de 23 pacientes brasileiros com CHH em que foram encontradas diversas variantes patogênicas. Dentre estas, a variante g.196C>T destacou-se por sua elevada frequência no grupo estudado, diferentemente do observado em pacientes de outras nacionalidades, sugerindo um possível efeito fundador (EF) para a população brasileira. Esse trabalho teve por objetivo realizar diferentes ensaios moleculares para auxiliar na compreensão da CHH, além de investigar a hipótese de uma origem ancestral comum da variante g.196C>T. O estudo foi dividido em 4 eixos, sendo três relacionados às pesquisas de caráter exploratório dos mecanismos da doença e um dedicado à análise do EF. Dentro deste último, utilizando um painel de marcadores do tipo TAG SNPs cuidadosamente selecionados, foi observado que cromossomos de diferentes regiões brasileiras carregando o nucleotídeo T na posição196 do gene RMRP compartilharam o haplótipo T/C/G/A (16/17 haplótipos), apontando para uma origem comum desta substituição de base no gene RMRP. Adicionalmente, foram realizadas análises de proteômica comparativa, evidenciando que o perfil proteômico dos leucócitos de pacientes e controles expressam proteínas que traduzem vias moleculares distintas, além de apresentar diferenças de expressão de proteínas importantes relacionadas aos fenótipos clínicos da doença. Também foram realizados ensaios de RT-qPCR que mostraram que tanto os níveis do RNA RMRP, quanto dos dois pequenos RNAs derivados de RMRP, estavam significativamente reduzidos nos pacientes em relação ao grupo controle. Por fim, com o intuito de tentar prever o impacto das variantes na estrutura tridimensional do RNA, foi realizada uma análise in silico que mostrou que as alterações patogênicas identificadas nos pacientes ocorreram tanto em regiões conservadas entre espécies de mamíferos quanto em domínios essenciais para o complexo ribonucleoproteico. Duas alterações estão localizadas em regiões associadas à biogênese dos pequenos RNAs derivados de RMRP. Além disso, foi possível observar que certas variantes podem alterar o pareamento de bases e a topologia da estrutura das alças da molécula, o que poderia influenciar na montagem do complexo RNAse MRP. Em conjunto, os dados desta tese lançam luz sobre diversos pontos ainda não explorados para CHH, além de dar suporte para novos estudos que tenham por objetivo viabilizar uma medicina de precisão, contribuindo para minimizar os impactos da doença e para a promoção da qualidade de vida dos pacientes.

Cartilage Hair Hypoplasia (CHH) is an autosomal recessive disease described by McKusick et al. in 1964 in the Amish community. Clinically, patients present metaphyseal bone dysplasia in different degrees of severity. In addition, hypotrichosis and immunodeficiency may also be present. At the molecular level, the condition is characterized by pathogenic variants of the RMRP gene. Although CHH has been described more than 60 years ago, the genotype-phenotype correlation is still not well-understood. This work is a continuation of the dissertation carried out at IFF/Fiocruz, during 2017 and 2018, in which a cohort of 23 Brazilian patients with CHH was described and several pathogenic variants were found. Among these, the high frequency of g.196C>T variant in the studied group called our attention, unlike that observed in patients of other nationalities, suggesting a possible founder effect (EF) in the Brazilian population. This work aimed to perform different molecular assays to aid in the understanding of CHH, in addition to investigating the hypothesis of a common ancestral origin of the g.196C>T variant. The study was divided into 4 axes, three related to exploratory research on disease mechanisms and one dedicated to the analysis of EF. Within the latter, using a carefully selected panel of TAG SNPs markers, it was observed that chromosomes from different Brazilian regions carrying T at nucleotide 196 of the RMRP gene shared the T/C/G/A haplotype (16/17 haplotypes), indicating a common origin of this base substitution at position 196 of the RMRP gene. Additionally, comparative proteomics analysis was performed, showing that the proteomic profile of leukocytes from patients and controls express proteins that translate distinct molecular pathways, in addition to presenting differences in the expression of proteins related to important clinical phenotypes of the disease. RT-qPCR assays were also performed, which showed that both RMRP RNA levels and the two RMRP-derived small RNAs were significantly reduced in patients compared to the control group. Finally, in order to try to predict the impact of the variants on the three-dimensional structure of the RNA, an in silico analysis was performed which showed that the pathogenic alterations identified in the patients occurred both in regions conserved between mammalian species and in domains essential for the ribonucleoprotein complex. Two alterations are located in regions associated with the biogenesis of RMRP-derived small RNAs. In addition, it was possible to observe that certain variants can change the base pairing and the topology of the structure of the molecule's loops, which could influence the assembly of the RNAse MRP complex. Together, the data from this thesis shed light on several points not yet explored for CHH, in addition to providing support for new studies that aim to enable a precision medicine toward CHH patients, helping to minimize the impacts of the disease and to promote quality of life of patients.