Exploring the overlap between alopecia areata and major depressive disorder: Epidemiological and genetic perspectives.

BACKGROUND: Research suggests that Alopecia areata (AA) and Major Depressive Disorder (MDD) show substantial comorbidity. To date, no study has investigated the hypothesis that this is attributable to shared genetic aetiology. OBJECTIVES: To investigate AA-MDD comorbidity on the epidemiological and molecular genetic levels. METHODS: First, epidemiological analyses were performed using data from a cohort of adult German health insurance beneficiaries (n = 1.855 million) to determine the population-based prevalence of AA-MDD comorbidity. Second, analyses were performed to determine the prevalence of MDD in a clinical AA case-control sample with data on psychiatric phenotypes, stratifying for demographic factors to identify possible contributing factors to AA-MDD comorbidity. Third, the genetic overlap between AA and MDD was investigated using a polygenic risk score (PRS) approach and linkage disequilibrium score (LDSC) regression. For PRS, summary statistics from a large MDD GWAS meta-analysis (PGC-MD2) were used as the training sample, while a Central European AA cohort, including the above-mentioned AA patients, and an independent replication US-AA cohort were used as target samples. LDSC was performed using summary statistics of PGC-MD2 and the largest AA meta-analysis to date. RESULTS: High levels of AA-MDD comorbidity were reported in the population-based (MDD in 24% of AA patients), and clinical samples (MDD in 44% of AA patients). MDD-PRS explained a modest proportion of variance in AA case-control status (R2  = 1%). This signal was limited to the major histocompatibility complex (MHC) region on chromosome 6. LDSC regression (excluding MHC) revealed no significant genetic correlation between AA and MDD. CONCLUSIONS: As in previous research, AA patients showed an increased prevalence of MDD. The present analyses suggest that genetic overlap may be confined to the MHC region, which is implicated in immune function. More detailed investigation is required to refine understanding of how the MHC is involved in the development of AA and MDD comorbidity.

Genomic profiling of late-onset basal cell carcinomas from two brothers with nevoid basal cell carcinoma syndrome.

BACKGROUND: Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant genetic disorder. It is commonly caused by mutations in PTCH1 and chiefly characterized by multiple basal cell carcinomas (BCCs) developing prior to the age of 30 years. In rare cases, NBCCS presents with a late onset of BCC development. OBJECTIVE: To investigate BCC tumorigenesis in two brothers, who showed characteristic features of NBCCS but developed their first BCCs only after the age of 40 years. Two other siblings did not show signs of NBCCS. RESULTS: We obtained blood samples from four siblings and nine BCCs from the two brothers with NBCCS. Whole exome sequencing and RNA sequencing revealed loss of heterozygosity (LOH) of PTCH1 in eight out of nine tumours that consistently involved the same haplotype on chromosome 9. This haplotype contained a germinal splice site mutation in PTCH1 (NM_001083605:exon9:c.763-6C>A). Analysis of germline DNA confirmed segregation of this mutation with the disease. All BCCs harboured additional somatic loss-of-function (LoF) mutations in the remaining PTCH1 allele which are not typically seen in other cases of NBCCS. This suggests a hypomorphic nature of the germinal PTCH1 mutation in this family. Furthermore, all BCCs had a similar tumour mutational burden compared to BCCs of unrelated NBCCS patients while harbouring a higher number of damaging PTCH1 mutations. CONCLUSIONS: Our data suggest that a sequence of three genetic hits leads to the late development of BCCs in two brothers with NBCCS: a hypomorphic germline mutation, followed by somatic LOH and additional mutations that complete PTCH1 inactivation. These genetic events are in line with the late occurrence of the first BCC and with the higher number of damaging PTCH1 mutations compared to usual cases of NBCCS.

An Open-Label Pilot Study to Evaluate the Efficacy of Tofacitinib in Moderate to Severe Patch-Type Alopecia Areata, Totalis, and Universalis.

Alopecia areata (AA) is a common autoimmune disease with a lifetime risk of ∼2%. In AA, the immune system targets the hair follicle, resulting in clinical hair loss. The prognosis of AA is unpredictable, and currently there is no definitive treatment. Our previous whole genome expression studies identified active immune circuits in AA lesions, including common γ-chain cytokine and IFN pathways. Because these pathways are mediated through JAK kinases, we prioritized clinical exploration of small molecule JAK inhibitors. In preclinical trials in mice, tofacitinib successfully prevented AA development and reversed established disease. In our tofacitinib trial in 12 patients with moderate to severe AA, 11 patients completed a full course of treatment with minimal adverse events. Following limited response to the initial dose (5 mg b.i.d.), the dose was escalated (10 mg b.i.d.) for nonresponding subjects. Eight of 12 patients demonstrated ≥50% hair regrowth, while three patients demonstrated <50% hair regrowth, as measured by Severity in Alopecia Tool scoring. One patient demonstrated no regrowth. Gene expression profiles and Alopecia Areata Disease Activity Index scores correlated with clinical response. Our open-label studies of ruxolitinib and tofacitinib have shown dramatic clinical responses in moderate to severe AA, providing strong rationale for larger clinical trials using JAK inhibitors in AA. ClinicalTrials.gov ID NCT02299297.

Multifaceted role of hair follicle dermal cells in bioengineered skins.

BACKGROUND: The method of generating bioengineered skin constructs was pioneered several decades ago; nowadays these constructs are used regularly for the treatment of severe burns and nonhealing wounds. Commonly, these constructs are comprised of skin fibroblasts within a collagen scaffold, forming the skin dermis, and stratified keratinocytes overlying this, forming the skin epidermis. In the past decade there has been a surge of interest in bioengineered skins, with researchers seeking alternative cell sources, or scaffolds, from which constructs can be established, and for more biomimetic equivalents with skin appendages. OBJECTIVES: To evaluate whether human hair follicle dermal cells can act as an alternative cell source for engineering the dermal component of engineered skin constructs. METHODS: We established in vitro skin constructs by incorporating into the collagenous dermal compartment: (i) primary interfollicular dermal fibroblasts, (ii) hair follicle dermal papilla cells or (iii) hair follicle dermal sheath cells. In vivo skins were established by mixing dermal cells and keratinocytes in chambers on top of immunologically compromised mice. RESULTS: All fibroblast subtypes were capable of supporting growth of overlying epithelial cells, both in vitro and in vivo. However, we found hair follicle dermal sheath cells to be superior to fibroblasts in their capacity to influence the establishment of a basal lamina. CONCLUSIONS: Human hair follicle dermal cells can be readily interchanged with interfollicular fibroblasts and used as an alternative cell source for establishing the dermal component of engineered skin both in vitro and in vivo.

Sex differences in genomics in lupus: girls with systemic lupus have high interferon gene expression while boys have high levels of tumour necrosis factor-related gene expression.

OBJECTIVES: Systemic lupus erythematosus (SLE) is a chronic disease occurring up to 15 times more frequently in females than males. This bias extends to possible differences in disease flares and response to therapy. This study was initiated to investigate the differences between girls and boys with childhood-onset SLE (cSLE) at the molecular level. METHOD: We analysed the Gene Expression Omnibus National Center for Biotechnology Information (GEO NCBI) microarray data available for 88 girls and 16 boys with treatment-naïve cSLE and compared the results to those from healthy controls. Transcriptional profiles were generated using the platforms of Affymetrix U133A and U133B gene chips and Bioconductor/R programming packages were used to process and compare the data. RESULTS: Girls with cSLE overexpressed an interferon (IFN)-α signature that was absent in boys. Boys with cSLE were observed to overexpress tumour necrosis factor-related genes that were absent in girls. Both boys and girls were observed to overexpress several genes related to granulopoeisis. CONCLUSIONS: Our results suggest a potential application of genomics to differentially predict response to therapy between females and males with SLE.

Novel compound heterozygous mutations in the desmoplakin gene cause hair shaft abnormalities and culminate in lethal cardiomyopathy.

A 2-month-old white girl born to nonconsanguineous parents presented to the dermatology department with hair loss that had commenced a few months after birth. Although her hair loss later stabilized, it remained sparse. By the age of 2 years, she was noted to have developed focal keratoderma over pressure points of the soles. Aged 5 years, she was admitted to hospital with a chest infection, and investigations at that point revealed that she had a dilated cardiomyopathy. Subsequent genetic investigations identified compound heterozygous mutations in the 3' end of the desmoplakin (DSP) gene (7567delAAGA and 6577G>A), explaining the cardiocutaneous phenotype.

Mutations in LPAR6/P2RY5 and LIPH are associated with woolly hair and/or hypotrichosis.

BACKGROUND: Woolly hair (WH) belongs to a family of disorders characterized by hair shaft anomalies that clinically presents with tightly curled hair, which can be divided into syndromic and non-syndromic forms of WH. We have recently identified mutations in both LPAR6/P2RY5 and LIPH that are associated with autosomal recessive woolly hair (ARWH). OBJECTIVE: To study the underlying genetic causes of autosomal woolly hair in Pakistani population. METHODS: We studied 10 Pakistani families with ARWH for mutations in LPAR6/P2RY5 and LIPH and then performed haplotype analysis to confirm their segregation in the families. RESULTS: We identified five mutations in LPAR6/P2RY5, among which three were recurrent and two were novel in eight Pakistani families. We then showed that two of the mutations in LPAR6/P2RY5 are founder mutations in Pakistani families. Moreover, we identified two recurrent mutations in the LIPH gene in two Pakistani families. CONCLUSION: Our study extends the spectrum of mutations in LPAR6/P2RY5 gene and underscores those mutations in LPAR6/P2RY5 and LIPH result in similar phenotypes.

Splice site mutations in the P-cadherin gene underlie hypotrichosis with juvenile macular dystrophy.

BACKGROUND: Hypotrichosis with juvenile macular dystrophy (HJMD; OMIM 601553) is a rare autosomal recessive disorder characterized by hypotrichosis with short scalp hair and progressive macular dystrophy leading to blindness between the second and the fourth decades of life. HJMD is caused by mutations in the P-cadherin gene (CDH3), a member of the family of classical cadherins. METHODS: We analyzed the DNA from members of 2 consanguineous Pakistani families with HJMD for mutations in the P-cadherin gene through direct sequencing. RESULTS: We identified 2 splice site mutations in the P-cadherin gene in these families. One was a novel mutation, Ivs12-2A-->G and the other a recurrent mutation, Ivs10-1G-->T. A screening assay for the novel mutation ruled out the possibility of a polymorphism. Using haplotype analysis, we determined that the mutation, Ivs10-1G-->T, is a founder mutation in the Pakistani population. CONCLUSION: We identified 2 splice site mutations in the CDH3 gene leading to HJMD, further enriching our understanding of HJMD versus ectodermal dysplasia, ectrodactyly and macular dystrophy syndrome.

A novel mutation in the cathepsin C gene in a Pakistani family with Papillon-Lefevre syndrome.

BACKGROUND: Papillon-Lefevre syndrome (PLS; OMlM 245000) is an autosomal recessive disease caused by mutations in cathepsin C (CTSC) gene and is characterized by palmoplantar keratoderma, psoriasiform lesion over the extensor surfaces and gingivitis followed by loss of teeth. CTSC gene is expressed in several tissues including the skin and cells of the immune system. In the skin, CTSC plays a role in differentiation and desquamation, whereas in the immune system, it activates serine proteases. OBJECTIVES: We analysed the molecular basis of PLS in a Pakistani family. METHODS: Genomic DNA was isolated from the sample according to standard techniques. All exons of the CTSC gene with adjacent sequences of exon-intron borders were amplified by PCR and directly sequenced. RESULTS: We identified a novel deletion mutation designated c.2ldelG (Leu7PhefsX57) in exon 1 of the CTSC gene, which probably results in the absence of CTSC protein. CONCLUSION: Our data further expand the spectrum of mutations in the CTSC gene underlying PLS.

Mutations in the keratin 9 gene in Pakistani families with epidermolytic palmoplantar keratoderma.

BACKGROUND: Keratins are heteropolymeric proteins that form the intermediate filament cytoskeleton in epithelial cells. The common basic structure of all keratins is organized in a central α-helical rod domain flanked by nonhelical, variable head and tail regions. Most mutations in keratins are found in the central α-helical rod domain. Keratin 9 (K9) is expressed only in the suprabasal layers of palmoplantar epidermis. Mutations in the keratin 9 gene (KRT9) have been shown to cause epidermolytic palmoplantar keratoderma (EPPK; OMIM 144200), an autosomal dominant genodermatosis characterized clinically by diffuse hyperkeratosis limited to the palms and soles, and histologically by epidermolysis in suprabasal layers of the epidermis. AIM: To elucidate the genetic basis of EPPK in five Pakistani families. METHODS: Using microsatellite markers localized to the areas around the type I keratin gene cluster on chromosome 17q21, genotyping of these families was performed, followed by sequencing of the KRT9 gene. RESULTS: The analysis resulted in the identification of two novel (p.M157K and p.Y454H) and two recurrent (p.M157T and p.R163Q) mutations in the KRT9 of all five families. All mutations occurred within the highly conserved helix initiation or termination motif of K9. CONCLUSIONS: The affected members of all five families possess mutations in the KRT9 gene that severely affect heterodimer formation with the type II keratin partner. The results of our study further underscore the crucial role of K9 protein in the palmoplantar epidermis.

Sabinas syndrome in monozygotic twins.

A pair of 2-year-old female monozygotic twins presented with short and brittle hair. There was marked reduction in hair density, and excessive curving of the eyelashes. Onychodystrophy was also evident. They also had developmental delay in verbal and motor skills. Neither their parents nor other relatives were known to be affected, and there was no history of consanguinity. Examination of the hair shaft under light microscopy showed trichoschisis, which was more evident under electron microscopy. Under polarized light, the hair shafts showed the pathognomonic 'tiger-tail' pattern. The level of sulphur in the hair was low. Both patients were negative for TTDN1 mutation. Clinical correlation was performed and the diagnosis of Sabinas syndrome was made. Sabinas syndrome is a very rare autosomal recessive disorder first described in a group of patients from a small community in north-eastern Mexico. It is diagnosable at birth, and its major symptoms include brittle hair, mental retardation and nail dysplasia. Structural hair abnormalities are seen by both light and electron microscopy.

Progressive symmetrical erythrokeratoderma: report of a Turkish family and evaluation for loricrin and connexin gene mutations.

We report here the first Turkish patient with progressive symmetric erythrokeratoderma. The patient's skin lesions appeared in the axillae at 3 months of age, and gradually spread to other flexural areas and to the trunk. Dermatological examination of the boy at 3.5 years of age revealed symmetric, hyperkeratotic plaques with erythematous outlines on the neck, wrists, armpits, trunk and posterior knees. The histopathological changes were nonspecific, including marked hyperkeratosis, irregular acanthosis, focal papillomatosis and perivascular lymphocytic infiltrates. Molecular studies of the loricrin (LOR), connexin 31 (GJB3) and connexin 30.3 (GJB4) genes did not identify a disease-causing mutation. These results further underline the genetic heterogeneity of the erythrokeratodermas.

FOXN1 homozygous mutation associated with anencephaly and severe neural tube defect in human athymic Nude/SCID fetus.

The forkhead, Fox, gene family comprises a diverse group of 'winged-helix' transcription factors that play important roles in development, metabolism, cancer and aging. Recently, several forkhead genes have been demonstrated to play critical roles in lymphocyte development and effector functions. Alterations of the FOXN1 gene in both mice and humans result in a severe combined immunodeficiency caused by an intrinsic defect of the thymus associated with congenital alopecia (Nude/severe combined immunodeficiency phenotype). FOXN1 is a member of the class of proteins involved in the development and differentiation of the central nervous system. We identified a human fetus homozygous for a mutation in FOXN1 gene who lacked the thymus and also had abnormal skin, anencephaly and spina bifida. Moreover, we found that FOXN1 gene is expressed in mouse developing choroid plexus. These observations suggest that FOXN1 may be involved in neurulation in humans.