Dermatology: Practical and Conceptual Original Article | Dermatol Pract Concept. 2025;15(1):4935 1 Di-Genic Inheritance in Genodermatoses: Insights from Two Consanguineous Cases in a Reference Lebanese Center within the Middle East and North Africa (MENA) Region Ayat Kadhi1,2,3, Lamiaa Hamie4,5, Edward Eid4, Georges Nemer1, Mazen Kurban1,5,6 1 Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar 2 College of Health and Sciences, University of Doha for Science and Technology, Doha, Qatar 3 Human Genetics Department, Sidra Medicine, Doha, Qatar 4 Department of Dermatology, Medical College of Wisconsin, Milwaukee, USA 5 Department of Dermatology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon 6 Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon Key words: Digenic inheritance, Genodermatoses, Whole-exome sequencing, Microarray Gene Expression DataSets Citation: Kadhi A, Hamie L, Eid E, Nemer G, Kurban M. Cases of Di-Genic Inheritance in Geno Dermatoses: Lessons from Consanguineous Cases in Lebanon. Dermatol Pract Concept. 2025;15(1):4935. DOI: https://DOI.org/10.5826/dpc.1501a4935 Accepted: November 24, 2024; Published: January, 2025 Copyright: ©2024 Kadhi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. *Corresponding Authors: Georges Nemer, Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar. E-mail: gnemer@hbku.edu.qa Mazen Kurban, Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar; Department of Dermatology, Medical College of Wisconsin, Milwaukee, USA; Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. E-mail: mk104@aub.edu.lb Introduction: Genodermatoses refer to a group of heterogenous rare genetic diseases with cutaneous expression. Several genodermatoses present with multisystem involvement that can range from mild to life-threatening conditions leading to increased morbidity and mortality. Objective: Given the paucity in the literature in the field of genodermatoses, especially in the Mid- dle East and North Africa (MENA) region, and building upon the first established genodermatoses database based in Lebanon, this study aimed to decipher the genetic basis of two different types of skin-inherited diseases (androgenic alopecia and vitiligo). Methods: We conducted a pilot study on two subjects with androgenic alopecia and vitiligo to in- vestigate the possibility of a digenic inheritance model as a potential underlying mechanism for these conditions. Whole exome sequencing (WES) and Gene Expression Omnibus (GEO) DataSets were employed to validate the methodology and provide a foundation for future, larger-scale studies. ABSTRACT 2 Original Article | Dermatol Pract Concept. 2025;15(1):4935 Introduction Genodermatoses refer to a diverse heterogenous group of rare inherited disorders characterized by cutaneous expres- sion and multisystem involvement, which increase patients’ morbidity and mortality. Currently, there are more than 350 various conditions under genodermatoses, and they are de- tectable soon after birth or early in life. These conditions are mainly divided into nine subcategories: disorders with malignant potential, disorders of keratinization, genetic blis- tering disorders, pigmentation disorders, neurocutaneous syndromes, vascular disorders, disorders of connective tis- sue, X-linked dominant disorders, and ectodermal dyspla- sia [1-3]. Most of these disorders are monogenic, but some disorders are reported to be digenic in cases with atypical clinical presentation such as epidermolysis bullosa simplex (KRT5 and KRT14 genes), hypotrichosis simplex( two un- linked loci 12q21.2-q22 and 16q21-q23.1), skin melanoma (MC1R and CDKN2A genes), and generalized pustular psoriasis with hypogammaglobulinemia (SEC6A1A and IL- 36RA genes) [4-7]. Herein, we will discuss androgenic alope- cia, vitiligo, and albinism. Androgenic alopecia (AGA MIM 109200) is a common, chronic, progressive hair loss disorder characterized by villus scalp hair/non-scarring alopecia in a distinctive manner. This pattern differs by sex: males typically experience vertex and bitemporal/frontal hair loss, while females experience hair loss starting from the vertex and mid-scalp, known as female pattern hair loss (FPHL) [8]. AGA affects 80% of males and 50% of females during the course of their life [9]. Vitiligo (MIM #606579) is a common chronic, acquired, idiopathic pigmentary disorder characterized by hypomela- nosis of skin, hair, or mucosae. Patients exhibit well-defined white macules that can be localized or generalized, immune deficiencies, and in some cases, sensorineural hearing loss. This disease is the most common cause of depigmentation, with a worldwide prevalence of 0.5%–2% in the general population [10]. Vitiligo affects both sexes equally and can appear at any age, but most commonly occurs between the second and third decades of life [11]. Oculocutaneous albinism (OCA) (MIM #203200) is a group of rare autosomal recessive disorders character- ized by hypopigmentation and ocular manifestations like decreased visual acuity, nystagmus, strabismus, and pho- tophobia. OCA is divided into two groups: syndromic and non- syndromic disorders; the most common syndromic OCA is Hermansky-Pudlak Syndrome (HPS), which is manifested by additional bleeding diathesis and more critical systemic comorbidities such as pulmonary fibrosis and immunodefi- ciency[12]. The prevalence of HPS is 1–2/1,000,000 individ- uals worldwide. These disorders have complicated etiologies; thus, a definitive diagnosis and treatment remains challenging. The apparent physical manifestations combined with a painful and challenging diagnosis course, leading to de- layed treatment, make these diseases psychologically dev- astating. In this study, we used the advent of emerging tools like WES and transcriptome analysis to unravel the diseases’ mechanisms, prompting a timely diagnosis which could lead to adequate targeted therapies treatment in genodermatoses. Methods Patient Recruitment The recruitment of the families was done at the Genoderma- toses Unit at the Department of Dermatology at the Ameri- can University of Beirut Medical Center. Clinical phenotypes were provided by the referring physician. The project was reviewed and approved by the Institutional Review Board (IRB) at the American University of Beirut Medical Center (Protocol Number: DER.MK.01), and written informed consent was obtained from the participants, or from their parents if minors, to collect blood samples and pictures. The patients included in this study were unrelated, represent- ing distinct familial backgrounds. Patient 1 was affected by androgenetic alopecia (AGA), while Patient 2 was affected by vitiligo and a family history of Hermansky-Pudlak Syn- drome (HPA). Results: We identified two gene variants FOXC1(p.His484Tyr) and SMARCD1 (p.Arg351Cys) responsible for androgenic alopecia and HPS1(p.Ser566Ter) and ITK (p.Pro521Leu) responsible for vitiligo. Further analysis using GEO DataSets confirmed the association between the genes involved in each each disease. Conclusion: This study identified novel candidate disease genes and inheritance model that could explain the underlying phenotypes that could open the door for a better-guided genomic approach for personalized treatment and early diagnosis. Original Article | Dermatol Pract Concept. 2025;15(1):4935 3 Whole Exome Sequencing and Variant Interpretation Peripheral blood samples were collected from patients and stored at 4° C. DNA was extracted from the specimens within one hour of collection. Whole exome sequencing (WES) was conducted for the probands and family members by Macro- gen Laboratory, Seoul, Korea. The FASTQ files were mapped to Human GRCh37/hg19 reference assembly using CLC Ge- nomics Workbench (version 20.0.4). Variant calling and anno- tation were performed using Illumina VariantStudio software version 3.0. To identify the mutations/variants that might lead to the diseases, stringent filter was applied (Figure 1). Detailed methods for this analysis can be found elsewhere [13]. GEO DataSets To explore the biological processes and pathways that are regulated in the diseases, we analyzed and the Gene Expres- sion Omnibus (GEO) DataSets using Ingenuity Pathway Analysis (IPA) software [14]. We curated datasets based on: (1) studies that have skin biopsies/blood samples to conduct expression profiling by microarray or RNA sequencing; (2) studies with information about the technology used; (3) stud- ies including normal and control groups. From that, we cu- rated these four datasets GSE90594, GSE36169, GSE90880, and GSE75819 (Table 1). Results Family 1: Androgenic Alopecia The proband (III.1, Figure 2A) is a 3-year-old female who visited the clinic due to features like adult male androgenetic alopecia, exhibiting hair loss and widening at the vertex and frontotemporal areas and had sparse eyebrows and eyelashes (Figure 2A and D). The results of the exome analysis yielded 75105 variants per sample before stringent filtering and 613 variants per sample after stringent filtering (Figure 1). After the first round of filtering, as we did not find any homo- zygous mutation in the patient that fit the stringent crite- ria, we looked for compound heterozygous mutations. Two potential variants were detected; the first variant is FOXC1 c.1450C>T, p.H484Y, which leads to a heterozygous mis- sense mutation with a predictive CADD score of 26.8 (Table 1 and Figure 2B and E). The variant is predicted to be likely pathogenic according to the ACMG [15] classifications and has a deleterious effect with a tree vote of 58|42 (del | benign) [16]. The variant was absent from the genomes/exomes da- tabases in gnomad[17] , ExAC [18], 1000G [19], and 300 Lebanese in-house exomes (Table 1). The other deleterious variant, SMARCD1 c.1051C>T, p.R351C (g.5537C>T), results in a heterozygous missense mutation with a CADD score of 33 (Table 1 and Figure 2C and F). The analysis of the GEO datasets GSE90594 and GSE36169 of individuals affected with androgenic alopecia compared to controls showed that FOXC1, an upstream regulator that leads to activation, had a z-score of 0.515, p-value 3.07E-03 and z-score of 4.233, p-value 3.64E-22, re- spectively. In the GSE90594 dataset, under the top diseases and biofunction, hair and skin development ranked as the second top function, with a p-value of 1.78-07-2.65E-65, and dermatological diseases ranked as the third top diseases, with a p-value of 2.22E-05-1.80E-68 (Table 2). For the net- work analysis, we found that there was a protein-protein interaction (PPI) between FOXC1 and SMARCD1 through SOX2 and YAP1 genes. We found that FOXC1 played a role in skin formation and keratinocyte differentiation, and that both FOXC1 and SMARCD1 increased the risk of skin can- cer (Figure 3). Family 2: Vitiligo and Albinism The patient (III.1, Figure 4A) was a 12-year-old female who presented to the clinic with vitiliginous lesions accompanied by immune deficiency. Her paternal uncle, patient II.3 (Fig- ure 4A), is a 48-year-old male diagnosed with albinism, with no immune deficiency. The exome analysis and filtering crite- ria is shown in Figure 2. The patient and her uncle harbored pathogenic nonsense variant HPS1c.1697C>A, p. Ser566Ter, that can lead to nonsense-mediated mRNA decay (NMD) (Figure 4B/D)[16] with a CADD score of 37. This variant was not present in the public databases. To explain the im- mune deficiency phenotype in the proband, we searched for immunoregulatory genes and found a deleterious homozy- gous missense variant ITK p. Pro521Leu with a CADD score of 29.6. (Figure 4C and E). The variant was present with a rare MAF in gnomad and 1000 Genome, and ExAC data- bases 0.00000796, 0.000007957, and 0.000008237, respec- tively (Table 1). IPA analysis of the GEO dataset GSE90880 revealed that immune cell trafficking was ranked the top function in the top diseases and biofunction, with a p-value range of 2.15E-54 – 5.91E-109 (Table 2), confirming the relevance to the underlying trait. No significant association was detected for GSE75819. For the upstream analysis, we found that ITK was an upstream regulator that leads to inhibition of the trait, with a z-score: -2.08, p-value 1.19E-06 and z-score: -1.813, p-value 9.91E-02, respectively. Finally, the network analysis showed that ITK and HPS1 were upstream of the TNF gene (Figure 5). Discussion WES provides an enormous amount of information about the genetic variation in familial cases exhibiting high phe- notypic variability with no clear monogenic segregation 4 Original Article | Dermatol Pract Concept. 2025;15(1):4935 or endocrinological abnormalities [21,22]. Our patient rep- resents the youngest case reported in the literature affected with AGA (consistent with male androgenic alopecia hair loss) with no prepubertal status or a family history of AGA, despite consanguinity originating from the granparents’ gen- eration, making it an intriguing case to further investigate. AGA is characterized by progressive hair follicular min- iaturization due to shortened anagen phase during hair cy- cle leading to disrupted hair growth cycles, dermal papilla size, and keratinocyte activities, which is mainly controlled by androgens through intracellular signaling of the hair fol- licle target cells. Androgen receptors (AR) are localized in dermal papilla cells (DPC) in a hair follicle, indicating that pattern [20]. This highlights the importance of following an unbiased approach to identify disease-causing variant/genes, as demonstrated by our current families with clinically and genetically heterogeneous cases. Transcriptional Players in AGA: FOXC1 and SMARCD1 AGA is well-known in adults but under-reported in pediatric and prepubertal children, making prevalence estimates chal- lenging. A retrospective report identified 57 of 483 pediatric patients (13%, ages 8–19) with AGA and a single case of a 6-year-old female with AGA, all diagnosed based on clinical manifestations, strong family history, genetic predisposition, Figure 1. A Summary of methods and results. ↑: Activation ↓: Inhibition N/S: not significant. Original Article | Dermatol Pract Concept. 2025;15(1):4935 5 Ta b le 1 . P he no ty pi c an d G en ot yp ic C ha ra ct er iz at io n of P at ie nt s. C lin ic al Fe at u re s G en e H G V S D N A R ef er en ce H G V S Pr o te in R ef er en ce C A D D Sc o re Si ft Po ly Ph en Pr ed ic te d Ef fe ct ( A C M G / M u ta ti o n Ta st er ) M A F (g n o m A D ) M A F (1 00 0 G en o m e) M A F (E xA C ) M A F (L eb an es e Ex o m es Po p u la ti o n ) 3- ye ar -o ld fe m al e w it h fe at ur es lik e m al e an dr og en ic al op ec ia (1 ) FO X C 1 (2 ) S M A R C D 1 (1 ) c. 14 50 C >T (2 ) :c .1 05 1C >T (1 ) p .H is 48 4T yr (2 ) p .A rg 35 1C ys (1 ) 26 .8 (2 ) 33 (1 ) D el et er io us (0 ) (2 ) D el et er io us (0 ) (1 ) Po ss ib ly da m ag in g (0 .7 75 ) (2 ) Po ss ib ly da m ag in g (0 .9 88 ) (1 ) U nc er ta in si gn ifi ca nc e (P M 2, PP 2) , L ik el y pa th og en ic (P P3 )/ D el et ri ou s (5 8| 42 ) (2 ) L ik el y Pa th og en ic (P M 1/ 2, P P2 /3 )/ / D el et ri ou s (6 4| 36 ) (1 ) 0/ 25 1, 48 6 (2 ) 1/ 25 1, 48 6 (0 .0 00 00 39 76 ) (1 ) 0/ 25 1, 36 0 (2 ) 0/ 25 1, 36 0 (1 ) 0 (2 ) 0 (1 ) 0/ 30 0 (2 ) 0/ 30 0 12 -y ea r- ol d m al e w it h vi ti lig in ou s le si on s an d im m un e de fic ie nc y/ 48 -y ea r- ol d pa te rn al un cl e af fe ct ed b y al bi ni sm (1 ) H P S1 (2 ) IT K (1 ) c. 16 97 C >A (2 ) c. 15 62 C >T (1 ) p. Se r5 66 Te r (2 ) p .P ro 52 1L eu (1 ) 37 (2 ) 29 .6 (1 )- (2 ) D el et er io us (0 ) (1 )- (2 ) Po ss ib ly da m ag in g (1 ) (1 ) Pa th og en ic (P V S1 , P M 2, P P3 )/ D el et ri ou s (1 93 |7 ) (2 ) U nc er ta in si gn ifi ca nc e (P M 2) L ik le y Pa th og en ic (P P3 )/ D el et ri ou s (7 3| 27 ) (1 ) 0/ 25 1, 36 0 (2 ) 2/ 25 1, 36 0 (0 .0 00 00 79 6) (1 ) 0/ 25 1, 36 0 (2 ) 2/ 25 1, 36 0 (0 .0 00 00 79 57 ) (1 ) 0 (2 ) 1/ 12 1, 40 4 (0 .0 00 00 82 37 ) (1 ) 0/ 30 0 (2 ) 0/ 30 0 6 Original Article | Dermatol Pract Concept. 2025;15(1):4935 transcription factors and RNA polymerase, which results in gene transcription followed by protein translation, which exerts the biological activity. This multi-step molecular pathway can be implicated in AGA pathogenesis. [25,28]. As such, the genes previously reported were linked to an- drogen signaling pathways such as (AR)/EDAR2, SRD5A1, SRD5A2, HSD17B2, HSD17B3, SHBG, AKR1C1, AKR1C2, AKR1C3, and FOXA2 [26,29-31]. Pathogenic variants in these genes were absent in our sequencing results, leading us to investigate other genes involved in AGA pathogenesis. DPC are the main target cells for androgen, which is shown in patient with AGA compared to non-AGA patients [23- 27]. Androgens such as progesterone, androstenedione, and testosterone are converted into a more potent androgen, di- hydrotestosterone (DHT), by the cytoplasmic 5α-reductase enzyme. DHT binds to AR in the cytoplasm, making AR- DHT complex, which translocates to the nucleus after di- merization. AR coactivators are recruited to this complex, which binds to the androgen-response element consistent with the DNA sequence. The coactivators connect AR and Figure 2. FOXC1 and SMARCD1 missense mutations segregates with androgenetic alopecia. (A) The pedigree of the familial androgenetic alopecia case with one affected member (red arrow) (+/+ normal genotype, +/- heterozygous genotype). (B)Primary structure of FOXC1 (553 amino acids), two Activation Domains (AD), Forkhead DNA-binding domain (FHD), Inhibitory domain (ID), the location of the current variant is identified in red. (C)Primary structure of SMARCD1(515 amino acids): SWIB domain and coiled-coil domains (C1, C2, and C3), the location of the current variant is identified in red, green variants are related to syndrome. (D) Patients’ phenotype representing male AGA hair loss pattern. (E)Integrated Genome Browser (IGV) visualization of the whole-exome sequencing results showing FOXC1 p.His484Tyr the T > C variant change in a heterozygous form for the patient (red and blue boxes, III.1- upper panel) and heterozygous in the father (red and blue box, II.2lower panels). (F) IGV visualization of the whole-exome sequencing results showing SMARCD1 p.Arg351Cys, the T > C variant change in the heterozygous form for the patient (red and blue box, III.1- upper panel) and heterozygous in the mother (red and blue box, II.1lower panels). Table 2. Results of Pathway Analysis from GEO Datasets.   Androgenic Alopecia Vitiligo GSE GSE90594 GSE36169 GSE90880 GSE75819 Platform GPL17077 GPL96 GPL8300 GPL6884 Sample size (affected: unaffected) 14:14 10:10 8:06 15:15 PubMed ID 28403520 22440736 28129744 28852211 Upstream Regulators FOXC1 activation (z-score: 0.515, p-value 3.07E-03) Disease and FOXC1 activation (z-score: 4.233, p-value 3.64E-22) ITK inhibition (z-score: -2.08, p-value 1.19E-06) ITK inhibition (z-score: -1.813, p-value 9.91E-02) Top diseases and biofunction Dermatological Diseases p-value (2.22E-05-1.80E-68) Hair and Skin Development and Function p-value(1.78-07-2.65E-65) Not Significant Immune Cell Trafficking p-value(2.15E-54 - 5.91E-109) Not Significant Original Article | Dermatol Pract Concept. 2025;15(1):4935 7 More importantly, a recent study showed that FOXC1 is highly expressed in human dermal papilla cells (DPCs) at the mRNA and protein level of patients affected with AGA [38], but no previous reports identified FOXC1 mutations with AGA. Our group previously showed a familial case of Axenfeld-Rieger Syndrome (ARS) where degenerated hair follicle cells were observed, which was explained through FOXC1/NFATC1 genetic axis [37]. Another report showed similar digenic inheritance of a mutation in FOXC1, but with PITX2 gene in ARS patient where the phenotypic sever- ity increased due to this inheritance [39]. Our mutation is in the activation domain (Figure 2B), and GEO DataSets show that FOXC1 is highly activated in AGA patients (Table 2). This led us to hypothesize that the mutation represented a partial gain of function. The involvement of both genes in AGA pathogenesis and in silico predictions support our hy- pothesis. Interestingly, a recent report identified SMARCD1 as one of the top 360 FOXC1 interactors, [40] and our in sil- ico analysis supports this interaction (Table 2 and Figure 3). Whether this interaction is crucial for hair follicle develop- ment remains to be explored. Our analysis revealed a potential combinatorial role for FOXC1 and SMARCD1 in the phenotype (Figures 3 and 6). SMARCD1 (SWI/SNF-related matrix-associated, actin- dependent regulator of chromatin, subfamily D, member 1) gene encodes BAF60A, a key protein in nucleosome-DNA interactions and found to have the highest induction of a strong interaction with AR. SMARCD1 directly interacts with the coactivator groove in the AR cofactor via its FxxFF motif directly in a hormone-dependent manner and acts as a promoter for the expression of TMPRSS2 gene [32]. The SMARCD1 mutation lies within the SWIB domain of the protein. A previous study identified several SMARCD1 vari- ants linked to a neurodevelopmental disorder with sparse or temporal hair deficiency as a phenotype (Figure 2B) [33]. The other player in this study is FOXC1 (Forkhead box C1), a transcriptional factor involved in cell differentiation and embryogenesis that plays a key role in human kera- tinocytes terminal differentiation [34]. It has been demon- strated that FOXC1 maintains and reinforces quiescence in self-renewing hair follicle stem cells in mice and humans leading to premature aging of these stem cells [35-37]. Figure 3. FOXC1 and SMARCD1 interactions and pathways using IPA software predictions tools. 8 Original Article | Dermatol Pract Concept. 2025;15(1):4935 Figure 4. HPS1 and ITK mutations segregate with Vitiligo and Albinism phenotypes. (A) The pedigree of the familial case with two affected members, indexed patient with red arrow (+/-heterozygous and -/- Homozygous genotype). (B) Primary structure of HPS1 (700 amino acids) with three domains: First Longin domain of Fuzzy (FUZ) protein 1,2, and 3, the current mutation is highlighted in red. (C) Primary structure of ITK (620 amino acids) with Pleckstrin homology (PH) , Brutos’s Tyrosine Kinase Cys-rich (BTK), Src Homology 3/2 (SH3/2), Protein Kinase Catalyic (TyrKc) domains. (D) Integrated Genome Browser (IGV)visualization of the whole-exome sequencing results showing HPS1; the T > G variant change in the heterozygous form for the heterozygous form for the uncle (red and green box, II.3 upper panels), the patient (red and orange box, III.1 middle panel), and a control (I.5). (E) IGV visualization of the whole-exome sequencing results showing ITK; p.Pro521Leu, the T > C variant change in the homozygous form for the patient (red box, III.1 lower panel) and not present in the uncle (II.2 upper panel), and a control (I.5). Figure 5. ITK and HPS1 interactions and pathways using IPA software predictions tools. Original Article | Dermatol Pract Concept. 2025;15(1):4935 9 Figure 6. FOXC1 And SMARCD1 role in hair follicle development (anagen phase). FOXC1 is expressed in dermal papilla cells and acts on keratinocytes differentiation while SMARCD1 acts on AR signaling pathway. Figure 7. HPS1 and ITK function in melanocyte and T-Cell. HPS1 acts on LROS such as melanosomes and lysosomes in a melanocyte while ITK plays a role in TCR signaling pathway in T-cell. 10 Original Article | Dermatol Pract Concept. 2025;15(1):4935 none of these genes were altered in our case. Interestingly, we found a novel missense variant in ITK p. Pro521Leu in our indexed patient (homozygous) which was absent in the uncle (Figure 4E). ITK (IL2 inducible T-cell kinase) belongs to TEC fam- ily kinase and is highly expressed in T cells and involved in T-cell receptor (TCR) signaling, cytokine release and differ- entiation regulation [57,58]. Mutations in ITK have been associated with benign inflammatory dermatoses that mim- ics cancer, eczema, lymphoproliferative disorder [59-62], and most importantly, a recent report have identified the same variant p.Pro521Leu in a patient with lymphoprolif- erative disorder where vitiligo was part of the phenotype [63]. Our IPA analysis revealed that ITK is inhibited in vit- iligo patients (Table 2), suggesting that our mutation acts as a partial loss of function. From melanocyte disruption by immunity involvement, we propose a di-genic inheritance pattern between HPS1 and ITK genes in vitiligo and found that ITK and HPS1 interacts with each other through TNF (Figures 5 and 7). We thus propose that a partial disruption of the TNF inhibition pathway imposed by the missense mutation in ITK combined with a partial gain of function through the truncated HPS1 protein will lead to an exaggerated increase in TNF and other cytokines such as IL-2,IL-6, IL-17 which are frequently observed in patients with vitiligo [64]. We cannot exclude a direct interaction between the proteins that would potentially be potentiated by the loss of the C- terminal domain of HPS1. Despite the small sample size, this study validated the technologies and methodologies, identified challenges with software and sequencing, and es- tablished a reference center to serve the underserved MENA region. Moreover, the samples were well preserved despite the region’s fluctuating temperatures, demonstrating the robustness of the protocols and paving the way for future large-scale studies. Conclusion In conclusion, this study unveils the culprit gene in familial cases of genodermatoses cases using WES, which is an im- portant tool to draw genotype–phenotype correlation. Ad- vances in the understanding of the disease mechanisms along with the changes in diagnostic patterns over time will likely contribute to the development of new therapeutic agents and better patient outcomes. References 1. Cheraghlou S, Lim Y, Choate KA. Mosaicism in genodermatoses. Clin Dermatol 2020;38:408-20.DOI: 10.1016/j.clindermatol .2020.03.008. A Permissive Environment for Interaction: Trafficking a Kinase A permissive environment is always a cordon for develop- ing differential phenotypes within a familial case. This is the case of our second family presented with two kinds of pig- mentation disorders: albinism and vitiligo, where epidermal/ hair follicle melanocyte disruption is a common pathway be- tween both disorders [41,42]. Since the hallmark of both diseases is melanocyte disrup- tion, we looked first for the genes that encode melanocyte proteins associated with vitiligo such as PTPN22, TYR, and MC1R [43] . We then looked for specific genes associated with OCA. We did not find any pathogenic variant neither in any of the genes that encode components of the four pro- tein complexes: adapter protein 3 (AP-3) and Biogenesis of Lysosome-related Organelles Complex 1, 2, and 3 (BLOC-1, BLOC-2, and BLOC-3) that are associate with the monogenic type, nor in the genes involved in the digenic mode of inheri- tance like TYR and OCA2 or SLC24A5 and OCA2 [44-47]. The only pathogenic mutation we uncovered is in the HPS1 gene which lead to a premature stop codon and a truncated protein HPS1 mutations which have been associated with OCA in several reports. HPS1 (c.9C > A) mutation counted for 5% in nonconsanguineous Chinese patients, two frame- shift variants in HPS1 (c.9delC and c.1477delA) in children with OCA, and two other gene mutations in Puerto Ricans, a 16-base pair (bp) duplication in HPS1 which accounted for 42.8% of OCA cases [48,49]. The homozygous HPS1 muta- tion accounts for the OCA phenotype in our family, but the heterozygous form alone does not explain the vitiligo pheno- type. We hypothesized that HPS1 could be a novel candidate gene in vitiligo since it is implicated in melanocyte activa- tion, proliferation, and differentiation.HPS1 is a BLOC-3 subunit which support the intracellular biogenesis and traf- ficking of lysosome and lysosome-related organelles (LROS) such as melanosomes, platelet dense bodies (also called delta granules), lamellar bodies of type II pneumocytes, and gran- ule proteins of cytotoxic and suppressor T cells and natural killer (NK) cells. As such, mutations in HPS1 leads to de- fective LROS trafficking and assembly [47,50]. By that, the proteins are mistargeted i.e., the proteins that are trafficked to plasma membrane are mistakenly targeted to intracellu- lar organelles like lysosome. This disrupts normal cell-cell interactions and chemotactic detection of migrating melano- cytes, affecting cell survival and proliferation. Consequently, it results in decreased melanocyte numbers in the epidermis and dermis and delayed melanocyte protein function. [51- 53]. The disruption of the melanocytes occur due to factors like oxidative stress from Reactive Oxygen Species (ROS), innate immunity, or adaptive immunity and gene responsible for that are XRP1, IFIH1, NLRP1, PTPRC , RERE,CTLA4, FOXP1, LPP, TSLP, IL12RA, GZMB, [54-56] however Original Article | Dermatol Pract Concept. 2025;15(1):4935 11 19. Genomes Project C, Auton A, Brooks LD, et al. A global ref- erence for human genetic variation. Nature 2015;526:68-74. 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