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SLC29A3 spectrum disorder, also known as histiocytosis‐lymphadenopathy plus syndrome (HLPS), presents a wide variety of multi‐systemic manifestations that can be mistaken for other conditions. Herein, we report a 9‐year‐old girl who presented with a complex clinical presentation since birth, including chronic generalized lymphadenopathy in association with hepatosplenomegaly, short stature, flexion contractures, hearing loss, hyperpigmentation, and heart anomalies. She was ultimately diagnosed with the SLC29A3 spectrum disorder. [ABSTRACT FROM AUTHOR]

H syndrome (HS) is a rare autosomal recessive genodermatosis characterised by cutaneous hyper­pigmentation, hypertrichosis, sclerodermatous thickening, and multisystemic involvement. It results from mutations in the SLC29A3 gene encoding the human equilibrative nucleoside transporter 3, leading to impaired histiocyte apoptosis and unchecked proliferation. We report the case of a 24-year-old Moroccan male who had a history of insulin-dependent diabetes mellitus. He deve­loped hyperpigmented skin patches with hypertrichosis and induration. Musculoskeletal findings included bilateral hallux valgus, pes planus, reducible flexion contractures of the proximal interphalangeal joints, and restricted ankle dorsiflexion. Additional findings consist of lymphadenopathy, hepatomegaly, hypogonadism, and ophthalmic manifestations. Investigations showed elevated sedimentation rate, anaemia, and osteopaenia. Ankle ultrasound revealed calcaneal enthesopathy and subcutaneous infiltration. In reporting this case, we aim to highlight the significant rheumatological involvement that can arise in patients with H syndrome and explore potential treatment options to improve the musculoskeletal findings.

Abstract Background The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. Methods In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. Results In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. Conclusion Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition.

Background: The SLC29A3 gene, which encodes a nucleoside transporter protein, is primarily located in intracellular membranes. The mutations in this gene can give rise to various clinical manifestations, including H syndrome, dysosteosclerosis, Faisalabad histiocytosis, and pigmented hypertrichosis with insulin-dependent diabetes. The aim of this study is to present two Iranian patients with H syndrome and to describe a novel start-loss mutation in SLC29A3 gene. Methods: In this study, we employed whole-exome sequencing (WES) as a method to identify genetic variations that contribute to the development of H syndrome in a 16-year-old girl and her 8-year-old brother. These siblings were part of an Iranian family with consanguineous parents. To confirmed the pathogenicity of the identified variant, we utilized in-silico tools and cross-referenced various databases to confirm its novelty. Additionally, we conducted a co-segregation study and verified the presence of the variant in the parents of the affected patients through Sanger sequencing. Results: In our study, we identified a novel start-loss mutation (c.2T > A, p.Met1Lys) in the SLC29A3 gene, which was found in both of two patients. Co-segregation analysis using Sanger sequencing confirmed that this variant was inherited from the parents. To evaluate the potential pathogenicity and novelty of this mutation, we consulted various databases. Additionally, we employed bioinformatics tools to predict the three-dimensional structure of the mutant SLC29A3 protein. These analyses were conducted with the aim of providing valuable insights into the functional implications of the identified mutation on the structure and function of the SLC29A3 protein. Conclusion: Our study contributes to the expanding body of evidence supporting the association between mutations in the SLC29A3 gene and H syndrome. The molecular analysis of diseases related to SLC29A3 is crucial in understanding the range of variability and raising awareness of H syndrome, with the ultimate goal of facilitating early diagnosis and appropriate treatment. The discovery of this novel biallelic variant in the probands further underscores the significance of utilizing genetic testing approaches, such as WES, as dependable diagnostic tools for individuals with this particular condition. [ABSTRACT FROM AUTHOR]

Background: The H syndrome is an autosomal recessive disease characterized by hyperpigmentation, hypertrichosis and sensorineural hearing loss. Methods: A mutation in the coding of the human equilibrative nucleoside transporter 3 (hENT3) within the SLC29A3 gene on chromosome 10q22 leads to the manifestation of this disease. In this report, we present two cases of H syndrome. Results: The first patient exhibits hyperpigmentation, hypogonadism, Type 1 diabetes mellitus, arthritis and osteoporosis. The second patient experiences hyperpigmentation, hypertrichosis, osteopenia and hypogonadism. Conclusion: Our objective is to broaden the clinical spectrum of H syndrome, highlighting the involvement of arthritis, hyperinflammation and low bone mineral density in individuals with this disorder. [ABSTRACT FROM AUTHOR]

H syndrome is a very rare auto inflammatory syndrome which is characterized by a constellation of symptoms mostly beginning with the letter H. Hypertrichosis, Hyperpigmentation, Hyperlipidemia, Hyperglycemia, Hypogonadism, Hepatomegaly, Hearing loss, Heart anomalies and short Height.Here we report a 14 years old boy with the diagnosis of H syndrome who was being treated for diabetes since he was 2 years old.

Abstract Background H Syndrome is a rare genetic condition caused by biallelic pathogenic variants in the SLC29A3 gene. It is characterized by a wide range of clinical manifestations, many of which are related to the immune-rheumatological field. These include scleroderma-like skin changes, deforming arthritis, and enlarged lymph nodes. The condition also features cardiac and endocrine defects, as well as hearing loss, for which the immune pathogenesis appears less clear. Immunomodulatory medications have been shown to improve many symptoms in recent experiences. Case presentation A 21-year-old girl was referred to our institute after being diagnosed with H syndrome. Her medical history was characterized by the development of finger and toe deformities, which developed since the first years of life and progressively worsened with clinodactyly. At 6 years of age, she was diagnosed with diabetes mellitus without typical autoantibodies and with bilateral sensorineural hearing loss. She also complained of frequent episodes of lymphadenopathy, sometimes with colliquation and growth retardation due to pancreatic insufficiency. It wasn’t until the genetic diagnosis of H syndrome that the continual increase in acute phase reactants was noticed, suggesting that an immunological pathogenesis may be the source of her problems. During her visit to our institute, she reported serious pain in both feet and hands and difficulty walking due to knee arthritis and muscle contractures. Conventional therapy with steroid injection in affected joints and methotrexate only led to partial improvement. After a thorough assessment of her inflammatory profile showing a high interferon score, the girl received treatment with baricitinib. Furthermore, based on recent data showing that SLC29A3 deficiency results in interferon production because of Toll-like Receptor 7 activation in lysosomes, hydroxychloroquine was also added. The combination of the two drugs resulted for the first time in a rapid and persistent normalization of inflammatory markers, paralleled by a dramatic improvement in symptoms. Conclusions We describe the results of inhibiting IFN inflammation in H syndrome and discuss how JAK inhibitors and antimalarials might represent a mechanistically based treatment for this orphan drug disorder.

Abstract Background The nucleoside transport capabilities of the human equilibrative nucleoside transporter-3 (hENT3) are disrupted by mutations in SLC29A3 (10q22.2), which are genes for the nucleoside transporter and are the cause of the unusual autosomal recessive disease known as H syndrome. As a result, histiocytic cells invade a number of organs. Case presentation A 17-year-old Syrian male was admitted to the internal medicine department with a one-month history of polyuria, polydipsia, general weakness, and pallor. He had a history of progressive bilateral sensorineural hearing loss and failure to gain weight for three years. Physical examination revealed various abnormalities, including scrotal mass, small penis and testicles, absence of pubic and axillary hair, joint abnormalities, short stature, hallux valgus, fibrous protrusion near the navel, and hyperpigmented non-itchy painful skin plaques. Clinical signs along with laboratory test results confirmed hyperglycemia, primary hypogonadism, osteopenia, and growth hormone deficiency. After a review of the relevant medical literature, this patient’s presentation of hyperglycemia with hypogonadism, hyperpigmentation, hallux valgus, hearing loss, hematological abnormalities, and short stature suggested the diagnosis of H syndrome. The patient received treatment with insulin and testosterone, leading to a significant improvement in his presenting symptoms. Conclusions H syndrome is a very rare condition, and the fact that the first case has only recently been reported in Syria serves to emphasize how rare it is. H Syndrome should be suspected if a patient has short stature with signs of hyperglycemia and other endocrine and cutaneous abnormalities. We are reporting this case to increase physicians’ awareness of this exceedingly rare and unique syndrome.

Background: H Syndrome is a rare genetic condition caused by biallelic pathogenic variants in the SLC29A3 gene. It is characterized by a wide range of clinical manifestations, many of which are related to the immune-rheumatological field. These include scleroderma-like skin changes, deforming arthritis, and enlarged lymph nodes. The condition also features cardiac and endocrine defects, as well as hearing loss, for which the immune pathogenesis appears less clear. Immunomodulatory medications have been shown to improve many symptoms in recent experiences. Case presentation: A 21-year-old girl was referred to our institute after being diagnosed with H syndrome. Her medical history was characterized by the development of finger and toe deformities, which developed since the first years of life and progressively worsened with clinodactyly. At 6 years of age, she was diagnosed with diabetes mellitus without typical autoantibodies and with bilateral sensorineural hearing loss. She also complained of frequent episodes of lymphadenopathy, sometimes with colliquation and growth retardation due to pancreatic insufficiency. It wasn't until the genetic diagnosis of H syndrome that the continual increase in acute phase reactants was noticed, suggesting that an immunological pathogenesis may be the source of her problems. During her visit to our institute, she reported serious pain in both feet and hands and difficulty walking due to knee arthritis and muscle contractures. Conventional therapy with steroid injection in affected joints and methotrexate only led to partial improvement. After a thorough assessment of her inflammatory profile showing a high interferon score, the girl received treatment with baricitinib. Furthermore, based on recent data showing that SLC29A3 deficiency results in interferon production because of Toll-like Receptor 7 activation in lysosomes, hydroxychloroquine was also added. The combination of the two drugs resulted for the first time in a rapid and persistent normalization of inflammatory markers, paralleled by a dramatic improvement in symptoms. Conclusions: We describe the results of inhibiting IFN inflammation in H syndrome and discuss how JAK inhibitors and antimalarials might represent a mechanistically based treatment for this orphan drug disorder. [ABSTRACT FROM AUTHOR]

Background: The nucleoside transport capabilities of the human equilibrative nucleoside transporter-3 (hENT3) are disrupted by mutations in SLC29A3 (10q22.2), which are genes for the nucleoside transporter and are the cause of the unusual autosomal recessive disease known as H syndrome. As a result, histiocytic cells invade a number of organs. Case presentation: A 17-year-old Syrian male was admitted to the internal medicine department with a one-month history of polyuria, polydipsia, general weakness, and pallor. He had a history of progressive bilateral sensorineural hearing loss and failure to gain weight for three years. Physical examination revealed various abnormalities, including scrotal mass, small penis and testicles, absence of pubic and axillary hair, joint abnormalities, short stature, hallux valgus, fibrous protrusion near the navel, and hyperpigmented non-itchy painful skin plaques. Clinical signs along with laboratory test results confirmed hyperglycemia, primary hypogonadism, osteopenia, and growth hormone deficiency. After a review of the relevant medical literature, this patient's presentation of hyperglycemia with hypogonadism, hyperpigmentation, hallux valgus, hearing loss, hematological abnormalities, and short stature suggested the diagnosis of H syndrome. The patient received treatment with insulin and testosterone, leading to a significant improvement in his presenting symptoms. Conclusions: H syndrome is a very rare condition, and the fact that the first case has only recently been reported in Syria serves to emphasize how rare it is. H Syndrome should be suspected if a patient has short stature with signs of hyperglycemia and other endocrine and cutaneous abnormalities. We are reporting this case to increase physicians' awareness of this exceedingly rare and unique syndrome. [ABSTRACT FROM AUTHOR]

H syndrome is a rare autosomal recessive genetic disorder characterized by the following clinical features: cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature, hallux valgus, hyperglycemia, fixed flexion contractures of the toe joints, and the proximal interphalangeal joints. In rare cases, autoinflammatory and lymphoproliferative manifestations have also been reported. This disorder is due to loss-of-function mutations in SLC29A3 gene, which encode the equilibrative nucleoside transporter ENT3. This deficiency leads to abnormal function and proliferation of histiocytes. H syndrome is part of the R-group of histiocytosis. We report two different cases, one was diagnosed in adulthood and the other in childhood. The first case reported is a 37-year-old woman suffering from H syndrome with an autoinflammatory systemic disease that begins in adulthood (fever and diffuse organ's infiltration) and with cutaneous, articular, auditory, and endocrinological manifestations since childhood. The second case reported is a 2-year-old girl with autoinflammatory, endocrine, and cutaneous symptoms (fever, lymphadenopathy, organomegaly, growth delay, and cutaneous hyperpigmentation). Homozygous mutations in SLC29A3 confirmed the diagnosis of H syndrome in both cases. Each patient was treated with Tocilizumab with a significant improvement for lymphoproliferative, autoinflammatory, and cutaneous manifestations. Both cases were reported to show the multiple characteristics of this rare syndrome, which can be diagnosed either in childhood or in adulthood. In addition, an overview of the literature suggested Tocilizumab efficiency. [ABSTRACT FROM AUTHOR]

H syndrome is a rare autosomal recessive genetic disorder characterized by the following clinical features: cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature, hallux valgus, hyperglycemia, fixed flexion contractures of the toe joints, and the proximal interphalangeal joints. In rare cases, autoinflammatory and lymphoproliferative manifestations have also been reported. This disorder is due to loss-of-function mutations in SLC29A3 gene, which encode the equilibrative nucleoside transporter ENT3. This deficiency leads to abnormal function and proliferation of histiocytes. H syndrome is part of the R-group of histiocytosis. We report two different cases, one was diagnosed in adulthood and the other in childhood. The first case reported is a 37-year-old woman suffering from H syndrome with an autoinflammatory systemic disease that begins in adulthood (fever and diffuse organ’s infiltration) and with cutaneous, articular, auditory, and endocrinological manifestations since childhood. The second case reported is a 2-year-old girl with autoinflammatory, endocrine, and cutaneous symptoms (fever, lymphadenopathy, organomegaly, growth delay, and cutaneous hyperpigmentation). Homozygous mutations in SLC29A3 confirmed the diagnosis of H syndrome in both cases. Each patient was treated with Tocilizumab with a significant improvement for lymphoproliferative, autoinflammatory, and cutaneous manifestations. Both cases were reported to show the multiple characteristics of this rare syndrome, which can be diagnosed either in childhood or in adulthood. In addition, an overview of the literature suggested Tocilizumab efficiency.

Diagnosis of histiocytosis can be difficult and one of the biggest challenges is to distinguish between reactive and neoplastic histiocytes on histology alone. Recently, OCT2 nuclear expression was reported in Rosai-Dorfman disease (RDD). Our purpose was to expand the testing of OCT2 on a broader variety of sporadic or H syndrome-related histiocytoses. Cases of histiocytoses were retrieved from the files of Ambroise Paré Pathology Department. All slides and molecular analyses were reviewed, and staining was completed with immunohistochemistry for OCT2. A total of 156 samples from different localizations were tested. Among sporadic cases, 52 patients had RDD, and 10 patients had mixed histiocytosis combining RDD with Erdheim Chester disease (ECD, n = 8), Langerhans cell histiocytosis (LCH, n = 2) or juvenile xanthogranuloma (JXG, n = 1). All these patients were positive for OCT2 in RDD characteristic histiocytes. Twenty-three patients had ECD and all but two (91% − 21/23) were negative for OCT2. By contrast, OCT2 was positive in 11/27 (41%) LCH and 6/16 (38%) JXG. Among the 10 samples of H syndrome-associated histiocytosis, 3 had typical RDD histology, 6 had unclassified histiocytosis, and one had mixed RDD-LCH; all were positive for OCT2. On 16 samples of granulomatous lymphadenitis, OCT2 was negative in epithelioid histiocytes. Our study shows that OCT2 has a sensitivity of 100% for RDD cases and mixed histiocytoses with an RDD component. It is negative in 92% of ECD but expressed in at least 38% of LCH, JXG, and C group histiocytoses. Finally, OCT2 is positive in all H syndrome-related histiocytoses, independent of their histology. [ABSTRACT FROM AUTHOR]

This case report presents the first H‐syndrome rarity in Iraq, a 12‐year‐old female patient who was attending the Rheumatology out clinic for progressive hands joint deformities. She has a history of a multi‐systemic collection of diseases with various clinical features that include beta thalassemia minor, sensorineural deafness, and celiac disease. [ABSTRACT FROM AUTHOR]

H Syndrome is a rare genodermatosis of autosomal recessive inheritance characterised by the presence of cutaneous and systemic manifestations. This syndrome is due to a mutation in the SLC9A3 gene encoding the hENTt3 transport protein. Still little known and rare, its diagnosis is difficult. Nearly 100 cases of H syndrome have been described, the majority of which were from Arab countries. The possible occurrence of other undiagnosed or misdiagnosed cases of syndrome H is highly probable due to the common features shared with other syndromes. We report two new cases of H syndrome from Morocco. One of them presents a unique association with celiac disease which has not been previously reported. The dermatologist's main goal is to diagnose the condition and enable appropriate follow-up and genetic counselling. [ABSTRACT FROM AUTHOR]

H syndrome is a systemic inherited autosomal recessive histiocytosis, with characteristic cutaneous findings accompanying systemic manifestations and a most common genetic mutation (OMIM 612391) as SLC29A3. The term “H Syndrome” is representative of presentation with hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, low height, and, occasionally, hyperglycemia. H syndrome is new and growing entity in medicine. This syndrome is not specific to a region or a nationality. There are very few treatment experiences on H Syndrome patients and most of them are unsatisfactory apart from hypertrichosis, which is able to treat almost permanently by hair removal lasers. Latest findings suggest that there is possibility of prevention of short stature or other cutaneous or systemic complications in this syndrome with earlier diagnosis and treatment. We searched Medline, Scopus, Web of Sciences, and Google Scholar, up to now and reviewed previous published papers with emphasis on treatment methods and its effects on certain common symptoms.

Abstract Background H syndrome is an autosomal recessive disorder caused by mutations in SLC29A3. Hyperpigmentation, hypertrichosis, hyperglycemia, and hearing loss are some characteristics of this disorder, and it has a prevalence of

Abstract This case report presents the first H‐syndrome rarity in Iraq, a 12‐year‐old female patient who was attending the Rheumatology out clinic for progressive hands joint deformities. She has a history of a multi‐systemic collection of diseases with various clinical features that include beta thalassemia minor, sensorineural deafness, and celiac disease.

Abstract Background Mutations in the SLC29A3 gene, which encodes the nucleoside transporter hENT3, have been implicated in syndromic forms of histiocytosis including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, Faisalabad histiocytosis and Familial Rosai–Dorfman disease (RDD). Herein, we report five new patients from a single family who present with phenotypes that associate features of H syndrome and Familial Rosai–Dorfman disease. Methods We investigated the clinical, biochemical, histopathological and molecular findings in five Tunisian family members' diagnosed with Familial RDD and/or H syndrome. The solute carrier family 29 (nucleoside transporters), member 3 (SLC29A3) gene was screened for molecular diagnosis using direct Sanger sequencing. Results Genetic analysis of all affected individuals revealed a previously reported missense mutation c.1088 G > A [p.Arg363Gln] in exon 6 of the SLC29A3 gene. Four affected members presented with clinical features consistent with the classical H syndrome phenotype. While their cousin’s features were in keeping with Familial Rosai–Dorfman disease diagnosis with a previously undescribed cutaneous RDD presenting as erythematous nodular plaques on the face. This report underlines the clinical variability of SLC29A3 disorders even with an identical mutation in the same family. Conclusion We report a rare event of 5 Tunisian family members' found to be homozygous for SLC29A3 gene mutations but showing a different phenotype severity. Our study reveals that despite a single mutation, the clinical expression of the SLC29A3 disorders may be significantly heterogeneous suggesting a poor genotype–phenotype correlation for the disease.

Abstract Background H syndrome (HS) is a rare autoinflammatory disease caused by a mutation in the solute carrier family 29, member 3 (SCL29A3) gene. It has a variable clinical presentation and little phenotype-genotype correlation. The pathognomonic sign of HS is cutaneous hyperpigmentation located mainly in the inner thighs and often accompanied by other systemic manifestations. Improvement after tocilizumab treatment has been reported in a few patients with HS. We report the first patient with HS who presented cardiogenic shock, multiorgan infiltration, and digital ischemia. Case presentation 8-year-old boy born to consanguineous parents of Moroccan origin who was admitted to the intensive care unit during the Coronavirus Disease-2019 (COVID-19) pandemic with tachypnoea, tachycardia, and oliguria. Echocardiography showed dilated cardiomyopathy and severe systolic dysfunction compatible with cardiogenic shock. Additionally, he presented with multiple organ dysfunction syndrome. SARS-CoV-2 polymerase chain reaction (PCR) and antibody detection by chromatographic immunoassay were negative. A previously ordered gene panel for pre-existing sensorineural hearing loss showed a pathological mutation in the SCL29A3 gene compatible with H syndrome. Computed tomography scan revealed extensive alveolar infiltrates in the lungs and multiple poor defined hypodense lesions in liver, spleen, and kidneys; adenopathy; and cardiomegaly with left ventricle subendocardial nodules. Invasive mechanical ventilation, broad antibiotic and antifungal coverage showed no significant response. Therefore, Tocilizumab as compassionate use together with pulsed intravenous methylprednisolone was initiated. Improvement was impressive leading to normalization of inflammation markers, liver and kidney function, and stabilising heart function. Two weeks later, he was discharged and has been clinically well since then on two weekly administration of Tocilizumab. Conclusions We report the most severe disease course produced by HS described so far in the literature. Our patient’s manifestations included uncommon, new complications such as acute heart failure with severe systolic dysfunction, multi-organ cell infiltrate, and digital ischemia. Most of the clinical symptoms of our patient could have been explained by SARS-CoV-2, demonstrating the importance of a detailed differential diagnosis to ensure optimal treatment. Although the mechanism of autoinflammation of HS remains uncertain, the good response of our patient to Tocilizumab makes a case for the important role of IL-6 in this syndrome and for considering Tocilizumab as a first-line treatment, at least in severely affected patients.

Agenesis of the inferior vena cava in H syndrome due to a novel SLC29A3 mutation. Keywords: H syndrome; mutation; SLC29A3; Indian; hyperpigmented plaques EN H syndrome mutation SLC29A3 Indian hyperpigmented plaques e138 e140 3 02/23/23 20230301 NES 230301 Dear Editor, H syndrome is a rare autosomal recessive disorder with a characteristic array of features such as hyperpigmentation, hypertrichosis, short height, hypogonadism, hepatosplenomegaly, hyperglycemia, hearing loss, and heart anomalies. [Extracted from the article]

Abstract H Syndrome is a rare genodermatosis. It may include facial involvement such as: facial telangiectasia, both hypo‐ and hyperpigmented lesions, hirsutism, swollen cheeks due to subcutaneous infiltration and eczematous lesions. We describe a new facial phenotype with dermoscopic and histological features in the spectrum of non‐Langerhans cell histiocytosis.

Yosra Zaimi,1 Myriam Ayari,1 Asma Mensi,1 Linda Bel Hadj Kacem,2 Leila Achouri,3 Meriem Bouzrara,4 Yosra Said,1 Leila Mouelhi,1 Radhouane Debbeche1 1Department of Gastroenterology, Charles Nicolle Hospital, Tunis, Tunisia; 2Department of Pathology, Charles Nicolle Hospital, Tunis, Tunisia; 3Department of Oncologic Surgery, University of Tunis El Manar, Tunis, Tunisia; 4Department of Radiology, Charles Nicolle Hospital, Tunis, TunisiaCorrespondence: Myriam AyariDepartment of Gastroenterology, Charles Nicolle Hospital, Boulevard 9 Avril 1938 Bab Saâdoun, Tunis, 1006, TunisiaEmail ayari.myriam@hotmail.frAbstract: H syndrome is an extremely rare autosomal recessive affection caused by biallelic mutations in the SLC29A3 gene encoding the human equilibrative nucleoside transporter hENT3. The hallmark signs are cutaneous consisting of hyperpigmentation and hypertrichosis patches. Besides, associated systemic manifestations are highly various reflecting phenotypic pleiotropism. Herein, we report a first case of pseudo-Meigs’ syndrome occurring in a young Tunisian H syndrome diagnosed patient with a novel homozygous frameshift mutation in exon 2 of the SLC29A3 gene: p.S15Pfs*86 inducing a premature stop codon. The patient developed ascites associated with left ovarian mass and she underwent surgery. After tumor resection, ascites disappeared rapidly. Histological examination showed serous cystadenoma of the ovary orienting the diagnosis towards pseudo-Meigs’ syndrome.Keywords: H syndrome, SLC29A3 gene, rare disease, pseudo-Meigs’ syndrome, Tunisian patient

H syndrome is a systemic inherited autosomal recessive histiocytosis, with characteristic cutaneous findings accompanying systemic manifestations and a most common genetic mutation (OMIM 612391) as SLC29A3. The term "H Syndrome" is representative of presentation with hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, low height, and, occasionally, hyperglycemia. H syndrome is new and growing entity in medicine. This syndrome is not specific to a region or a nationality. There are very few treatment experiences on H Syndrome patients and most of them are unsatisfactory apart from hypertrichosis, which is able to treat almost permanently by hair removal lasers. Latest findings suggest that there is possibility of prevention of short stature or other cutaneous or systemic complications in this syndrome with earlier diagnosis and treatment. We searched Medline, Scopus, Web of Sciences, and Google Scholar, up to now and reviewed previous published papers with emphasis on treatment methods and its effects on certain common symptoms. [ABSTRACT FROM AUTHOR]

Background: Mutations in the SLC29A3 gene, which encodes the nucleoside transporter hENT3, have been implicated in syndromic forms of histiocytosis including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, Faisalabad histiocytosis and Familial Rosai–Dorfman disease (RDD). Herein, we report five new patients from a single family who present with phenotypes that associate features of H syndrome and Familial Rosai–Dorfman disease. Methods: We investigated the clinical, biochemical, histopathological and molecular findings in five Tunisian family members' diagnosed with Familial RDD and/or H syndrome. The solute carrier family 29 (nucleoside transporters), member 3 (SLC29A3) gene was screened for molecular diagnosis using direct Sanger sequencing. Results: Genetic analysis of all affected individuals revealed a previously reported missense mutation c.1088 G > A [p.Arg363Gln] in exon 6 of the SLC29A3 gene. Four affected members presented with clinical features consistent with the classical H syndrome phenotype. While their cousin's features were in keeping with Familial Rosai–Dorfman disease diagnosis with a previously undescribed cutaneous RDD presenting as erythematous nodular plaques on the face. This report underlines the clinical variability of SLC29A3 disorders even with an identical mutation in the same family. Conclusion: We report a rare event of 5 Tunisian family members' found to be homozygous for SLC29A3 gene mutations but showing a different phenotype severity. Our study reveals that despite a single mutation, the clinical expression of the SLC29A3 disorders may be significantly heterogeneous suggesting a poor genotype–phenotype correlation for the disease. [ABSTRACT FROM AUTHOR]

H syndrome is a rare autosomal recessive disorder with clinical features comprising: hyperpigmentation, hypertrichosis, hearing loss, heart anomalies, low height, hypogonadism and hepatosplenomegaly. H syndrome results from loss‐of‐function mutations in SLC29A3 which leads to abnormal proliferation and function of histiocytes. Herein, we discuss the considerable phenotypic heterogeneity detected in a consanguineous Egyptian family comprising of four affected siblings, two of which are monozygotic twin and the possible therapeutics. The phenotypic variability may be attributed to the role of histiocytes in the tissue response to injury. Such variable expressivity of H syndrome renders the diagnosis challenging and delays the management. The different treatment approaches used for this rare entity are reviewed. [ABSTRACT FROM AUTHOR]

Background: H syndrome (HS) is a rare autoinflammatory disease caused by a mutation in the solute carrier family 29, member 3 (SCL29A3) gene. It has a variable clinical presentation and little phenotype-genotype correlation. The pathognomonic sign of HS is cutaneous hyperpigmentation located mainly in the inner thighs and often accompanied by other systemic manifestations. Improvement after tocilizumab treatment has been reported in a few patients with HS. We report the first patient with HS who presented cardiogenic shock, multiorgan infiltration, and digital ischemia. Case presentation: 8-year-old boy born to consanguineous parents of Moroccan origin who was admitted to the intensive care unit during the Coronavirus Disease-2019 (COVID-19) pandemic with tachypnoea, tachycardia, and oliguria. Echocardiography showed dilated cardiomyopathy and severe systolic dysfunction compatible with cardiogenic shock. Additionally, he presented with multiple organ dysfunction syndrome. SARS-CoV-2 polymerase chain reaction (PCR) and antibody detection by chromatographic immunoassay were negative. A previously ordered gene panel for pre-existing sensorineural hearing loss showed a pathological mutation in the SCL29A3 gene compatible with H syndrome. Computed tomography scan revealed extensive alveolar infiltrates in the lungs and multiple poor defined hypodense lesions in liver, spleen, and kidneys; adenopathy; and cardiomegaly with left ventricle subendocardial nodules. Invasive mechanical ventilation, broad antibiotic and antifungal coverage showed no significant response. Therefore, Tocilizumab as compassionate use together with pulsed intravenous methylprednisolone was initiated. Improvement was impressive leading to normalization of inflammation markers, liver and kidney function, and stabilising heart function. Two weeks later, he was discharged and has been clinically well since then on two weekly administration of Tocilizumab. Conclusions: We report the most severe disease course produced by HS described so far in the literature. Our patient's manifestations included uncommon, new complications such as acute heart failure with severe systolic dysfunction, multi-organ cell infiltrate, and digital ischemia. Most of the clinical symptoms of our patient could have been explained by SARS-CoV-2, demonstrating the importance of a detailed differential diagnosis to ensure optimal treatment. Although the mechanism of autoinflammation of HS remains uncertain, the good response of our patient to Tocilizumab makes a case for the important role of IL-6 in this syndrome and for considering Tocilizumab as a first-line treatment, at least in severely affected patients. [ABSTRACT FROM AUTHOR]

This is the first report of constrictive pericarditis (CP) in a 16‐year‐old boy with H syndrome with pericardial involvement predominantly over the right ventricle with favorable response to anti‐inflammatory treatment. H syndrome, first reported in 2008, is a new auto‐inflammatory syndrome with multiorgan involvement due to mutation in the SLC29A3 gene. We described the echocardiographic characteristics of asymmetric pericardial involvement and presented the cardiac computed tomography angiographic and magnetic resonance imaging findings. We reviewed the echocardiographic signs of CP, introduced tricuspid E/A respiratory alternans as a novel echocardiographic sign of right ventricular dominant CP, and explained the underlying mechanism. [ABSTRACT FROM AUTHOR]

Abstract We present a case of a retrospectively diagnosed H syndrome in a man who died of a probable heart infarction. We highlight the importance of recognizing cutaneous hallmarks of this syndrome for better clinical management and prevention.

H Syndrome is a rare genodermatosis. It may include facial involvement such as: facial telangiectasia, both hypo‐ and hyperpigmented lesions, hirsutism, swollen cheeks due to subcutaneous infiltration and eczematous lesions. We describe a new facial phenotype with dermoscopic and histological features in the spectrum of non‐Langerhans cell histiocytosis. [ABSTRACT FROM AUTHOR]

A possibility of SARS-CoV2 induced HLH with persistent MIS-C was retained in view of persistent fever associated with rash, pancytopenia, SARS-CoV2 antibody positivity and raised inflammatory markers. Histiocytosis-lymphadenopathy plus syndrome revealed by repeated secondary hemophagocytic lymphohistiocytosis Keywords: H syndrome; HLH; intravenous immunoglobulin; multisystem inflammatory syndrome; post-viral immune dysregulation; SARS-CoV2 EN H syndrome HLH intravenous immunoglobulin multisystem inflammatory syndrome post-viral immune dysregulation SARS-CoV2 1 3 3 05/30/22 20220501 NES 220501 We report the follow-up of an immunocompetent child with histiocytosis-lymphadenopathy plus syndrome who had previously developed hemophagocytic lymphohistiocytosis (HLH), secondary to Parvovirus infection.1 The patient first presented in 2019, at three years of age, with complaints of fever, rash, hepatosplenomegaly, and pancytopenia. [Extracted from the article]

Background: H syndrome is a multisystem inflammatory disease caused by mutations in the SLC29A3 gene (OMIM #602782). The protein product, hENT3, is a nucleoside transporter essential for DNA salvage synthesis. Clinical manifestations are hyperpigmentation, hypertrichosis, hepatosplenomegaly, hearing loss, heart anomalies, hypogonadism, short stature, skeletal deformities, and diabetes mellitus. Laboratory findings are consistent with inflammatory processes. Structural kidney anomalies have been described in 6% of patients. Case reports: Three family members with genetically diagnosed H syndrome (c.1279G>A, p.Gly427Ser). Two of them presented with hypoalbuminemia and nephrotic range proteinuria. Kidney ultrasound was normal. Kidney biopsy performed in one patient presenting with generalized peripheral pitting edema revealed membranous nephropathy. Different treatments including ACE inhibitors, corticosteroids, and immunomodulatory agents failed to improve the clinical outcome. Conclusions: Generalized peripheral pitting edema and glomerulopathy broaden the clinical spectrum of H syndrome. Periodic bloodwork and urinalysis are recommended. [ABSTRACT FROM AUTHOR]

Biallelic mutations in SLC29A3 cause histiocytosis-lymphadenopathy plus syndrome, also known as H syndrome (HS). HS is a complex disorder, with ~ 25% of patients developing autoinflammatory complications consisting of unexplained fevers, persistently elevated inflammatory markers, and unusual lymphadenopathies, with infiltrating CD68+, S100+, and CD1a− histiocytes, resembling the immunophenotype found in Rosai-Dorfman disease (RDD). We investigated the transcriptomic profiles of monocytes, non-activated (M0), classically activated (M1), and alternatively activated macrophages (M2) in two patients with HS, one without autoinflammatory (HS1) and one with autoinflammatory complications (HS2). RNA sequencing revealed a dysregulated transcriptomic profile in both HS patients compared to healthy controls (HC). HS2, when compared to HS1, had several differentially expressed genes, including genes associated with lymphocytic-histiocytic predominance (e.g. NINL) and chronic immune activation (e.g. B2M). The transcriptomic and cytokine profiles of HS patients were comparable to patients with SAID with high levels of TNF. SERPINA1 gene expression was found to be upregulated in all patients studied. Moreover, higher levels of IFNγ were found in the serum of both HS patients when compared to HC. Gene ontology (GO) enrichment analysis of the DEGs in HS patients revealed the terms "type I IFN," "IFNγ signaling pathway," and "immune responses" as the top 3 most significant terms for monocytes. Gene expression analysis of lymph node biopsies from sporadic and H syndrome-associated RDD suggests common underlying pathological process. In conclusion, monocytes and macrophages from both HS patients showed transcriptomic profiles similar to SAIDs and also uniquely upregulated IFNγ signature. These findings may help find better therapeutic options for this rare disorder. [ABSTRACT FROM AUTHOR]

H syndrome is a complex multi‐organ disorder with autosomal recessive inheritance. The skin manifestations include early onset hyperpigmentation and hypertrichosis, followed by skin induration often diagnosed as scleromyxedema and morphea. There is no effective treatment. Our objective was to study the efficacy of mycophenolate mofetil in a patient with genetically confirmed H syndrome. We sought the genetic cause of H syndrome with whole‐exome sequencing (WES) of the proband. Genome‐wide homozygosity mapping (HM) provided additional evidence for causality of the variant suggested by WES. Here, we report a patient with characteristic clinical features of H syndrome, and the diagnosis was confirmed by identification of a homozygous SLC29A3 mutation (p.Gly437Arg). The patient was initially treated with prednisolone and cyclosporine, but after development of side‐effects she was placed on mycophenolate mofetil. After the treatment with mycophenolate mofetil was initiated, resolution of hyperpigmentation was noted, and no new lesions developed during an 18‐month follow‐up period. Thus, mycophenolate mofetil could be considered as a safe and partially effective treatment of H syndrome. [ABSTRACT FROM AUTHOR]

H syndrome (OMIM 602782) is a recently defined autosomal recessive genodermatosis. Cutaneous findings of H syndrome include hyperpigmentation, hypertrichosis, and induration, while hearing loss, heart anomalies, hepatomegaly, hypogonadism, hyperglycemia (diabetes mellitus), low height (short stature), hallux valgus (flexion contractures), and hematological abnormalities are the extracutaneous abnormalities. We report a novel homozygous missense mutation, c.416T > C p.(Leu139Pro), in the SLC29A3 (NM_001174098.1) gene in two sisters with H syndrome presenting with different phenotypes. [ABSTRACT FROM AUTHOR]

H syndrome is a recently described autosomal recessive genodermatosis with cutaneous phenotypes of varying severity and multi-system involvement. Patients suffering from this disorder can be easily mistaken for sclerodermoid conditions. The radiological findings of H syndrome are typical but have been described only anecdotally. We present a case of a 29 year old male patient of H syndrome with typical radiological features.

This case report describes a case of H syndrome with characteristic cutaneous hyperpigmentation, hypertrichosis, sclerodermatous thickening, and multisystem involvement such as hearing loss and heart anomaly in an Indian patient. There are around 100 cases of this rare, autosomal recessive genodermatosis reported in the literature, out of which 10 cases are from the Indian population. The aim of this paper is to increase awareness about this novel inherited form of histiocytosis and insist on the role of dermatologists to identify such patients in our population where consanguinity is prevalent.

• H Syndrome is described as an autoinflammatory disease associating with autoimmune features, such as vitiligo and pure red cell anemia. • Here it is defined as a combined immunodeficiency with decreased T cells and recent thymic emigrants, increased effector memory CD4+ T cells. • Lysosomal instability and mitochondrial stress present in patient's cells may underlie the mechanism of autoinflammation. • Immunoglobulin therapy and low dose corticosteroids were useful in the resolution of pure red cell anemia and elevated acute phase reactants. H Syndrome is an autosomal recessive (AR) disease caused by defects in SLCA29A3 gene. This gene encodes the equilibrative nucleoside transporter, the protein which is highly expressed in spleen, lymph node and bone marrow. Autoinflammation and autoimmunity accompanies H Syndrome (HS). The aim was to further elucidate the mechanisms of disease by molecular studies in a patient with SLC29A3 gene defect. Mitochondrial dysfunction, lysosomal integrity, cytokine response in response to stimulation with different pattern recognition receptor ligands, and circulating cell-free mitochondrial-DNA(ccf-mtDNA) level in plasma were analyzed compared to controls to understand the cellular triggers of autoinflammation. RNA sequencing (RS) analyses were also performed in monocytes before/after culture with lipopolysaccharide. Patient had progressive destructive arthropathy in addition to clinical findings due to combined immunodeficiency. Pure red cell aplasia (PRCA), vitiligo, diabetes, multiple autoantibody positivity, lymphopenia, increased acute phase reactants were present. Recent thymic emigrants (RTE), naïve T cells were decreased, effector memory CD4 + T cells, nonclassical inflammatory monocytes were increased. Patient's peripheral blood mononuclear cells secreted more IL-1β and IL-6, showed lysosomal disruption and significant mitochondrial dysfunction compared to healthy controls. Plasma ccf-mtDNA level was significantly elevated compared to age-matched controls (p < 0.05). RNA sequencing studies revealed decreased expression of NLR Family Caspase Recrument-Domain Containing 4(NLRC4), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4(PFKFB4), serine dehydratase(SDS), heparan sulfate(Glucosamine) 3-O-sulfotransferase 1(HS3ST1), neutral cholesterol ester hydrolase 1 (NCEH1), and interleukin-8 (IL-8) in patient's monocytes compared to controls. Longstanding PRCA, which is possibly autoimmune, resolved after initiating monthly intravenous immunoglobulins (IVIG) and low dose steroids to the patient. Although autoinflammation and autoimmunity are reported in HS, by functional analyses we here show in the present patient that over-active inflammasome pathway in HS might be related with mitochondrial and lysosomal dysfunction. Increased plasma ccf-mtDNA may be used as a biomarker of inflammasomopathy in HS. HS should be included in the classification of primary immunodeficiency diseases. [ABSTRACT FROM AUTHOR]

Abstract Background H Syndrome is an autosomal recessive disorder characterized by cutaneous hyperpigmentation, hypertrichosis, and induration with numerous systemic manifestations. The syndrome is caused by mutations in SLC29A3, a gene located on chromosome 10q23, which encodes the human equilibrative transporter 3 (hENT3). Less than 100 patients with H syndrome have been described in the literature, with the majority being of Arab descent, and only a few from North America. Case presentation Here we report five pediatric patients from three medical centers in the United States who were identified to have H syndrome by whole exome sequencing. These five patients, all of whom presented to pediatric rheumatologists prior to diagnosis, include two of Northern European descent, bringing the total number of Caucasian patients described to three. The patients share many of the characteristics previously reported with H syndrome, including hyperpigmentation, hypertrichosis, short stature, insulin-dependent diabetes, arthritis and systemic inflammation, as well as some novel features, including selective IgG subclass deficiency and autoimmune hepatitis. They share genetic mutations previously described in patients of the same ethnic background, as well as a novel mutation. In two patients, treatment with prednisone improved inflammation, however both patients flared once prednisone was tapered. In one of these patients, treatment with tocilizumab alone resulted in marked improvement in systemic inflammation and growth. The other had partial response to prednisone, azathioprine, and TNF inhibition; thus, his anti-TNF biologic was recently switched to tocilizumab due to persistent polyarthritis. Another patient improved on Methotrexate, with further improvement after the addition of tocilizumab. Conclusion H syndrome is a rare autoinflammatory syndrome with pleiotropic manifestations that affect multiple organ systems and is often mistaken for other conditions. Rheumatologists should be aware of this syndrome and its association with arthritis. It should be considered in patients with short stature and systemic inflammation, particularly with cutaneous findings. Some patients respond to treatment with biologics alone or in combination with other immune suppressants; in particular, treatment of systemic inflammation with IL-6 blockade appears to be promising. Overall, better identification and understanding of the pathophysiology may help devise earlier diagnosis and better treatment strategies.

H syndrome is a rare autosomal recessive syndrome characterised by constellation of clinical features and systemic manifestations including cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, hearing loss, heart anomalies, hypogonadism, hyperglycaemia, low height, and hallux valgus. We report a case of this syndrome with typical clinical findings. We report this case citing the rarity of this uncommon entity.

Background: The term "H syndrome" was coined to denote the major clinical findings, which include hyperpigmentation, hypertrichosis, hearing loss, hepatosplenomegaly, hyperglycaemia, hypogonadism, hallux flexion contractures, and short height. Objective: To report the clinical, endocrinological, histochemical, and genetic findings of three siblings. Methods: Skin and liver biopsies were taken to investigate the histochemical characteristics of hyperpigmented hypertrichotic skin lesions and massive hepatomegaly. The levels of basal serum thyroid hormones, oestradiol, total testosterone, follicle-stimulating hormone, luteinising hormone, and stimulated growth hormone (GH) were measured to investigate the endocrine aspects of the syndrome. Mutation analysis was carried out in all six exons and exon-intron boundaries of SLC29A3 by direct sequencing. Results: Physical examination of the patients revealed common charac-teristic findings of H syndrome. Additional clinical findings were sectorial iris atrophy in the younger sister. Laboratory evaluation revealed microcytic anaemia, markedly increased erythrocyte sedimentation rate and C-reactive protein levels, and humoral immune deficiency in the younger siblings, who presented with recurrent fever and sinopulmonary infection. Two different GH stimulation tests revealed GH deficiency in the younger sister with short stature. Liver and skin biopsies revealed polyclonal lymphohistiocytic and plasma cell infiltration. Sequencing of SLC29A3 in the three siblings revealed a novel homozygous mutation in exon 6, which caused the transition of arginine to tryptophan. Conclusion: This study not only extended the clinical and mutation spectrum of SLC29A3 in H syndrome, but also showed that short children should be assessed according to the guidelines for short stature in children. [ABSTRACT FROM AUTHOR]

Abstract H syndrome is a rare monogenic autosomal recessive disease with characteristic cutaneous findings and multisystem involvement. The aim of this study is to present an Iranian patient with H syndrome and to describe a novel frameshift mutation in SLC29A3 gene. The patient was diagnosed with a few small areas of hyperpigmentation and accompanying hypertrichosis in the lumbar area of her back. Her clinical phenotypes included short stature, hepatosplenomegaly, facial widespread bilateral telangiectatic lesions, bilateral hypertrophy of the parotid gland, upper extremity flexion contracture, elevated inflammatory markers (ESR, CRP) and diabetes mellitus. The identification of a novel homozygous frameshift mutation (c.307_308delTT, p.F103Ter) in SLC29A3 gene , together with the characteristic clinical manifestations of H syndrome, provided accurate diagnosis for this patient. [ABSTRACT FROM AUTHOR]

Background: H syndrome ([OMIM] 602782) is an autosomal recessive disorder with systemic manifestations and characteristic skin lesions, caused by mutations of the SLC29A3 gene. Short stature and diabetes mellitus are the major endocrine problems related to H syndrome, however, clear data from clinical follow-up of H syndrome patients is lacking in the literature. Case presentation: Here, we present follow-up of a Turkish girl diagnosed with H syndrome at the age of 10 with a homozygous 310(c.933T>A, p.C310X) early stop codon mutation on exon 6 of the SLC29A3 gene. She had severe short stature non-responsive to growth hormone (GH) treatment and gluten-free diet despite low GH levels and celiac antibody positivity. She developed insulin dependent diabetes mellitus (IDDM) symptoms 6 years after the initial diagnosis. Conclusions: H syndrome patients can develop IDDM years after characteristic symptoms. Short stature in H syndrome patients may not respond to GH replacement or gluten-free diet alone. [ABSTRACT FROM AUTHOR]

Pigmentary hypertrichosis and non-autoimmune insulin-dependent diabetes mellitus (PHID) syndrome is associated with severe chronic inflammation and cardiomyopathy, and represents a new monogenic autoinflammatory syndrome. Hyperpigmentation, hypertrichosis, SLC29A3 gene, H syndrome Keywords: H syndrome; hyperpigmentation; hypertrichosis; SLC29A3 gene EN H syndrome hyperpigmentation hypertrichosis SLC29A3 gene 269 271 3 03/03/21 20210101 NES 210101 CASE REPORT An 18-year-old male of Arabic origin, diagnosed of insulin-dependent diabetes mellitus with poor metabolic control since the age of 2 years, was seen because of skin lesions present since about 10 years of age. [Extracted from the article]

We present a case of a retrospectively diagnosed H syndrome in a man who died of a probable heart infarction. We highlight the importance of recognizing cutaneous hallmarks of this syndrome for better clinical management and prevention. [ABSTRACT FROM AUTHOR]

Background: H syndrome (OMIM 612391) is a recently described autosomal recessive genodermatosis characterized by indurated hyperpigmented and hypertrichotic skin, as well as other systemic manifestations. Most of the cases occurred in the Middle East areas or nearby countries such as Spain or India. The syndrome is caused by mutations in solute carrier family 29, member 3 (SLC29A3), the gene encoding equilibrative nucleoside transporter 3. The aim of this study was to identify pathogenic SLC29A3 mutations in a Chinese patient clinically diagnosed with H syndrome. Methods: Peripheral blood samples were collected from the patient and his parents. Genomic DNA was isolated by the standard method. All six SLC29A3 exons and their flanking intronic sequences were polymerase chain reaction (PCR)-amplified and the PCR products were subjected to direct sequencing. Results: The patient, an 18-year-old man born to a nonconsanguineous Chinese couple, had more extensive cutaneous lesions, involving both buttocks and knee. In his genomic DNA, we identified a novel homozygous insertion-deletion, c. 1269_1270delinsT, in SLC29A3. Both of his parents were carriers of the mutation. Conclusions: We have identified a pathogenic mutation in a Chinese patient with H syndrome.

H syndrome is a rare autosomal recessive disorder with characteristic dermatological findings consisting of hyperpigmentation and hypertrichosis patches mainly located on the inner thighs and multisystemic involvement including hepatosplenomegaly, hearing loss, heart abnormalities and hypogonadism. The aim of this study was to conduct a clinical and genetic investigation in five unrelated Tunisian patients with suspected H syndrome. Hence, genetic analysis of the SLC29A3 gene was performed for four patients with a clinical diagnosis of H syndrome. We identified a novel frame-shift mutation in the SLC29A3 gene in a female patient with a severe clinical presentation. Furthermore, we report two mutations previously described, the p.R363Q mutation in a male patient and the p.P324L mutation in two patients of different age and sex. This paper extends the mutation spectrum of H syndrome by reporting a novel frame-shift mutation, the p.S15Pfs*86 in exon 2 of SLC29A3 gene and emphasizes the relevance of genetic testing for its considerable implications in early diagnosis and clinical management. [ABSTRACT FROM AUTHOR]

H syndrome is a recently described autosomal recessive genodermatosis with cutaneous phenotypes of varying severity and multi-system involvement. Patients suffering from this disorder can be easily mistaken for sclerodermoid conditions. The radiological findings of H syndrome are typical but have been described only anecdotally. We present a case of a 29 year old male patient of H syndrome with typical radiological features. [ABSTRACT FROM AUTHOR]