Tongue microarchitecture and functional characterization of the lingual papillae in the desert hedgehog (Paraechinus aethiopicus).

The present work attempted to provide a comprehensive description of the morphoanatomical, histological, and ultrastructural characteristics of the tongue in the desert hedgehog (Paraechinus aethiopicus), and to correlate lingual modifications to the feeding lifestyle. Five adult male hedgehogs were utilized in our investigation. The macroscopic observations revealed elongated, with a moderately pointed apex, tongue and the tongue dorsum lacks both lingual prominence and median sulcus. The main subdivisions of the tongue are radix linguae (root), corpus linguae (body), and apex linguae (apex). The tongue dorsum carries two types of mechanical (conical and filiform) and gustatory (fungiform and circumvallate) papillae. The lingual apex is characterized by the existence of a unique encapsulated muscular structure. Additionally, the lingual glands were interposed between the muscular strands and no lingual glands were detected on the lingual apex. The dorsal surface of the lingual apex exhibited the highest level of keratinization as revealed by histochemical staining while the root showed moderate staining. The topography of the tongue was investigated by scanning electron microscopy (SEM). The obtained results are important to provide basic knowledge that can contribute to better understanding of the nourishment, feeding habits and behavior in this species. Furthermore, the addition of the newly investigated species may help us to determine the evolutionary relationships among species.

Cloning, tissue distribution of desert hedgehog (dhh) gene and expression profiling during different developmental stages of Pseudopleuronectes yokohamae.

As a crucial member of the Hedgehog (Hh) protein family, desert hedgehog (dhh) plays a vital role in multiple developmental processes, cell differentiation and tissue homeostasis. However, it is unclear how it regulates development in fish. In this study, we cloned and characterized the dhh gene from Pseudopleuronectes yokohamae. The full-length cDNA of Pydhh comprises 3194 bp, with a 1386 bp open reading frame (ORF) that encodes a polypeptide of 461 amino acids with a typical HH-signal domain, Hint-N and Hint-C domains. Multiple sequence alignment revealed that the putative PyDHH protein sequence was highly conserved across species, especially in the typical domains. Phylogenetic analysis showed that the PyDHH clustered within the Pleuronectiformes. Real-time quantitative PCR showed that Pydhh was detected in fourteen different tissues in adult-female and adult-male marbled flounder, and nine different tissues in juvenile fish. During early embryonic development stages, the expression of Pydhh was revealed high levels at hatching stage of embryo development. Moreover, the relative expression of Pydhh was significantly higher in the juvenile liver than adults', and higher in the female skin than the male skin. To further investigate its location, the in situ hybridization (ISH) assay was performed, the results showed that the hybridization signal was obviously expressed in the immune organs of Pseudopleuronectes yokohamae, with weak signal expression in the other tissues. Our results suggested that Pydhh is highly conserved among species and plays a vital role in embryonic development and formation of immune related organs.

Novel compound heterozygous mutations in the desert hedgehog (DHH) gene in cases of siblings with 46,XY disorders of sexual development.

BACKGROUND: Disorders of sex development (DSD) are congenital disorders in which the development of the chromosomal, gonadal, or anatomical sex is atypical. Mutations in various genes can impede gonadal development, hormone synthesis, or hormone function and cause DSD. METHODS: Exome sequencing was performed for two siblings with 46,XY DSD. All mutations identified by exome sequencing were confirmed by Sanger sequencing. RESULTS: The 13-month-old younger sibling had a female appearance of the external genital with a clitoris that was assessed as Prader III and scored 2 in the external masculinization score evaluative test. The 16-year-old elder sibling had severe hypospadias. Exome sequencing revealed compound heterozygous mutations in exon 3 of DHH in the siblings with 46,XY DSD. The frameshift mutation (NM_021044.3: c.602delC) was derived from the father and was predicted to be deleterious. The (c.937G > T) substitution mutation was derived from the mother. CONCLUSIONS: Novel compound heterozygous mutations of DHH led to 46,XY DSD in two siblings. This study expands the phenotypic mutation spectra of DHH in patients with 46,XY DSD.

The Desert Hedgehog Signalling Pathway in Human Gonadal Development and Differences of Sex Development.

While the Hedgehog signalling pathway is implicated in numerous developmental processes and maladies, variants in the Desert Hedgehog (DHH) ligand underlie a condition characterised by 46,XY gonadal dysgenesis with or without peripheral neuropathy. We discuss here the role and regulation of DHH and its signalling pathway in the developing gonads and examine the current understanding of how disruption to this pathway causes this difference of sex development (DSD) in humans.

Changes in the feeding behavior and habitat use of the desert hedgehog Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), in Saudi Arabia / Mudanças no comportamento alimentar e no uso do hábitat do ouriço-do-deserto Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), na Arábia Saudita

Due to the urbanization and human invasion of the natural environments, great changes have been occurred on the food composition and feeding ecology of several animals especially those are sharing human his habitat in fields, wadis and gardens. The desert hedgehogs Paraechinus aethiopicus populations inhabiting different localities in Saudi Arabia were studied by using stomach contents analysis between February 2015 and October 2019. Precise analysis of stomach contents of 55 hedgehogs showed that the food of P. aethiopicus is highly diverse and highly influenced with effect of human on the environment including cooked rice, insects, plant materials, eggshells, worms, garbage and remnants of mammals and birds. Diet composition showed seasonal variations that are apparently associated with changes in the availability of different food items. The present results clearly showed that P. aethiopicus is an omnivorous mammal, capable of adapting to a great variety of dietary compositions in the study sites.

Devido à urbanização e invasão humana dos ambientes naturais, grandes mudanças têm ocorrido na composição alimentar e ecologia alimentar de vários animais, especialmente aqueles que estão compartilhando seu hábitat humano em campos, wadis e jardins. As populações de ouriços-do-deserto Paraechinus aethiopicus que habitam diferentes localidades na Arábia Saudita foram estudadas usando análise de conteúdo estomacal entre fevereiro de 2015 e outubro de 2019. A análise precisa do conteúdo estomacal de 55 ouriços mostrou que a alimentação de P. aethiopicus é altamente diversa e altamente influenciada com efeito de humanos no meio ambiente, incluindo arroz cozido, insetos, materiais vegetais, cascas de ovo, vermes, lixo e restos de mamíferos e pássaros. A composição da dieta apresentou variações sazonais que aparentemente estão associadas a mudanças na disponibilidade de diferentes itens alimentares. Os presentes resultados mostraram claramente que P. aethiopicus é um mamífero onívoro, capaz de se adaptar a uma grande variedade de composições dietéticas nos locais de estudo.

Changes in the feeding behavior and habitat use of the desert hedgehog Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), in Saudi Arabia / Mudanças no comportamento alimentar e no uso do hábitat do ouriço-do-deserto Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), na Arábia Saudita

Due to the urbanization and human invasion of the natural environments, great changes have been occurred on the food composition and feeding ecology of several animals especially those are sharing human his habitat in fields, wadis and gardens. The desert hedgehogs Paraechinus aethiopicus populations inhabiting different localities in Saudi Arabia were studied by using stomach contents analysis between February 2015 and October 2019. Precise analysis of stomach contents of 55 hedgehogs showed that the food of P. aethiopicus is highly diverse and highly influenced with effect of human on the environment including cooked rice, insects, plant materials, eggshells, worms, garbage and remnants of mammals and birds. Diet composition showed seasonal variations that are apparently associated with changes in the availability of different food items. The present results clearly showed that P. aethiopicus is an omnivorous mammal, capable of adapting to a great variety of dietary compositions in the study sites.

Devido à urbanização e invasão humana dos ambientes naturais, grandes mudanças têm ocorrido na composição alimentar e ecologia alimentar de vários animais, especialmente aqueles que estão compartilhando seu hábitat humano em campos, wadis e jardins. As populações de ouriços-do-deserto Paraechinus aethiopicus que habitam diferentes localidades na Arábia Saudita foram estudadas usando análise de conteúdo estomacal entre fevereiro de 2015 e outubro de 2019. A análise precisa do conteúdo estomacal de 55 ouriços mostrou que a alimentação de P. aethiopicus é altamente diversa e altamente influenciada com efeito de humanos no meio ambiente, incluindo arroz cozido, insetos, materiais vegetais, cascas de ovo, vermes, lixo e restos de mamíferos e pássaros. A composição da dieta apresentou variações sazonais que aparentemente estão associadas a mudanças na disponibilidade de diferentes itens alimentares. Os presentes resultados mostraram claramente que P. aethiopicus é um mamífero onívoro, capaz de se adaptar a uma grande variedade de composições dietéticas nos locais de estudo.

Changes in the feeding behavior and habitat use of the desert hedgehog Paraechinus aethiopicus (Ehrenberg 1832, Eulipotyphla: Erinaceidae), in Saudi Arabia

Abstract Due to the urbanization and human invasion of the natural environments, great changes have been occurred on the food composition and feeding ecology of several animals especially those are sharing human his habitat in fields, wadis and gardens. The desert hedgehogs Paraechinus aethiopicus populations inhabiting different localities in Saudi Arabia were studied by using stomach contents analysis between February 2015 and October 2019. Precise analysis of stomach contents of 55 hedgehogs showed that the food of P. aethiopicus is highly diverse and highly influenced with effect of human on the environment including cooked rice, insects, plant materials, eggshells, worms, garbage and remnants of mammals and birds. Diet composition showed seasonal variations that are apparently associated with changes in the availability of different food items. The present results clearly showed that P. aethiopicus is an omnivorous mammal, capable of adapting to a great variety of dietary compositions in the study sites.

Resumo Devido à urbanização e invasão humana dos ambientes naturais, grandes mudanças têm ocorrido na composição alimentar e ecologia alimentar de vários animais, especialmente aqueles que estão compartilhando seu hábitat humano em campos, wadis e jardins. As populações de ouriços-do-deserto Paraechinus aethiopicus que habitam diferentes localidades na Arábia Saudita foram estudadas usando análise de conteúdo estomacal entre fevereiro de 2015 e outubro de 2019. A análise precisa do conteúdo estomacal de 55 ouriços mostrou que a alimentação de P. aethiopicus é altamente diversa e altamente influenciada com efeito de humanos no meio ambiente, incluindo arroz cozido, insetos, materiais vegetais, cascas de ovo, vermes, lixo e restos de mamíferos e pássaros. A composição da dieta apresentou variações sazonais que aparentemente estão associadas a mudanças na disponibilidade de diferentes itens alimentares. Os presentes resultados mostraram claramente que P. aethiopicus é um mamífero onívoro, capaz de se adaptar a uma grande variedade de composições dietéticas nos locais de estudo.

Gonadal differentiation during embryonic and fetal development of male New Zealand rabbits (Oryctolagus cuniculus) / Diferenciación gonadal durante el desarrollo embrionario y fetal de conejos machos neozelandeses (Oryctolagus cuniculus)

SUMMARY: The rabbit is considered an ideal animal model for studies that describe abnormalities in the testicles due to the similar morphogenetic mechanisms of sexual development and diseases commonly found in humans. The aim of this study was to determine the male sexual differentiation of the New Zealand rabbit (Oryctolagus cuniculus) through development. The gestational age was estimated and classified as 9, 12, 14, 16, 18, 20, 23 and 28 gestational days. The morphological and sexual determination were performed by histological analysis of the reproductive tract in the embryos and fetuses (9-28 days) as well as by immunohistochemistry- Desert hedgehog-Dhh- (testis-specific protein on Y chromosome- 16, 20, 23 days and adult rabbits). Gonads were observed from the 14th day in an undifferentiated stage and with homogeneous aspect. Sexual differentiation was observed from the 16th day with presence of cells forming gonadal cords and Dhh+ cells in the gonadal parenchyma. From the 18th gestational day testicular cords were observed, which evolved into organized seminiferous tubules. The formation of the efferent ducts and ductus deferens and epididymis was observed on the 20th and 23rd days, respectively. The differentiation of the external genitalia occurred from the 23rd days from the anogenital distance and was identified to identify the penile structures. In summary, the features of the sexual differentiation were determined by observation of the Dhh+ protein in embryos from the 16th day to adulthood, and the morphological particularities observed from the 18th gestational day, determined by differentiation of the external genitalia from the 23rd day.

RESUMEN: El conejo se considera un modelo animal ideal para estudios que describen anomalías a nivel testícular debido a que presenta mecanismos morfogenéticos similares al desa- rrollo sexual y enfermedades que se encuentran comúnmente en los seres humanos. El objetivo de este estudio fue determinar la diferenciación sexual masculina del conejo de Nueva Zelanda (Oryctolagus cuniculus) a través del desarrollo. La edad gestacional se estimó y clasificó en 9, 12, 14, 16, 18, 20, 23 y 28 días gestacionales. La determinación morfológica y sexual se realizó mediante análisis histológico del tracto reproductivo en los embriones y fetos (9 - 28 días) así como mediante inmunohistoquímica -Desert hedgehog-Dhh- (proteína testicular específica en el cromosoma Y- 16, 20, 23 días y conejos adultos). Las gónadas se observaron a partir del día 14 en un estadio indiferenciado y con aspecto homogéneo. Se observó diferenciación sexual a partir del día 16 con presencia de células formadoras de cordones gonadales y células Dhh+ en el parénquima gonadal. A partir del día 18 de gestación se observaron cordones testiculares, que evolucionaron a túbulos seminíferos organizados. La formación de los conductos eferentes, deferentes y del epidídimo se observó a los 20 y 23 días, respectivamente. La diferenciación de los genitales externos ocurrió a partir del día 23 desde la distancia anogenital y se utilizó para identificar las estructuras del pene. En conclusión, las características de la diferenciación sexual se determinaron mediante la observación de la proteína Dhh en embriones desde el día 16 hasta la edad adulta, y las particularidades morfológicas observadas a partir del día 18 de gestación, determinadas por diferenciación de los genitales externos a partir del día 23.

Effects of vitamin e on the epithelial-mesenchymal transition in testicular development exposed to valproic acid / Efectos de la vitamina e en la interacción epitelio-mesenquimático en el desarrollo testicular expuesto a ácido valproico

SUMMARY: In testicular differentiation, somatic cells must adopt a specific destiny towards sustentacular, peritubular and interstitial cells, being fundamental for the morphogenesis of seminiferous tubules, mediated by morphogens such as Desert Hedgehog (DHH), insulin-like growth factor-1 (IGF-1) and fibroblastic growth factor 2 (FGF-2). Its alteration could be related to failures in the development mechanisms, such as those caused by valproic acid (VPA), which can be reversed with vitamin E (VE). The objective of the study was to evaluate the epithelial-mesenchymal transition (EMT) in the testicular development of mice exposed to VPA and VE. 12 groups of pregnant female mice were formed that were separated by days post-coital (dpc) at 12.5 dpc, 17.5 dpc and 6 weeks postnatal, each one subdivided into 4 groups of 5 pregnant women each. Subgroups received different treatments from the beginning to the end of gestation orally: 600 mg/kg of VPA, 600 mg/kg of VPA and 200 IU of VE, 200 IU of VE and the control group 0.3 mL of 0.9% physiological solution. Immunohistochemistry was performed for the detection of DHH, IGF-1 and FGF-2. Immunolocalization of DHH was observed in all stages, with more evident significant differences in integrated optical density (IOD) and percentage of immunoreaction area at 6 weeks postnatal, being lower in the VPA group. In IGF-1, lower intensity and distribution of immunostaining was observed in the fetal and pubertal stages in the VPA groups, a similar situation with FGF-2, but only evident at 17.5 dpc, with significant differences. These results demonstrate that VPA can alter EMT between somatic cells in testicular development, with VE being an agent capable of attenuating this process.

RESUMEN: En la diferenciación testicular, es necesario que las células somáticas adopten un destino específico hacia células sustentaculares, peritubulares e intersticiales, siendo fundamental para la morfogénesis de los túbulos seminíferos, mediado por morfógenos como Desert Hedgehog (DHH), Factor de Crecimiento Fibroblástico 2 (FGF-2) y Factor de Crecimiento símil a Insulina (IGF-1). Su alteración se podría relacionar a fallas en los mecanismos de desarrollo, como los que ocasiona el ácido valproico (VPA), los cuales pueden ser revertidos con la vitamina E (VE). El objetivo de estudio fue evaluar la transición epitelio-mesenquimática (EMT) en el desarrollo testicular de ratones expuestos a VPA y VE. Se conformaron 12 grupos de ratones hembra gestantes que se separaron por días post-coital (dpc) a los 12.5 dpc, 17.5 dpc y 6 semanas post-natal, cada uno subdividido en 4 grupos de 5 gestantes cada uno. Cada subgrupo recibió diferentes tratamientos desde el inicio hasta el término de la gestación vía oral: 600 mg/kg de VPA, 600 mg/kg de VPA y 200 UI de VE, 200 UI de VE y el grupo control 0,3 mL de solución fisiológica 0,9%. Se realizó técnica inmunohistoquímica para la detección de DHH, IGF-1 y FGF-2. Se observó la inmunolocalización de DHH en todos los estadios, con diferencias significativas más evidentes en la densidad óptica integrada (IOD) y porcentaje de área de inmunoreacción a las 6 semanas post-natal, siendo menor en el grupo VPA. En IGF-1, se observó en la etapa fetal y puberal menor intensidad y distribución de la marcación en los grupos VPA, situación similar con la inmunomarcación de FGF-2, pero sólo evidenciándose a los 17.5 dpc, con diferencias significativas. Estos resultados demuestran que el VPA puede alterar la EMT entre las células somáticas en el desarrollo testicular, siendo la VE un agente capaz de atenuar este proceso.

Hedgehog signaling in gastrointestinal carcinogenesis and the gastrointestinal tumor microenvironment.

The Hedgehog (HH) signaling pathway plays important roles in gastrointestinal carcinogenesis and the gastrointestinal tumor microenvironment (TME). Aberrant HH signaling activation may accelerate the growth of gastrointestinal tumors and lead to tumor immune tolerance and drug resistance. The interaction between HH signaling and the TME is intimately involved in these processes, for example, tumor growth, tumor immune tolerance, inflammation, and drug resistance. Evidence indicates that inflammatory factors in the TME, such as interleukin 6 (IL-6) and interferon-γ (IFN-γ), macrophages, and T cell-dependent immune responses, play a vital role in tumor growth by affecting the HH signaling pathway. Moreover, inhibition of proliferating cancer-associated fibroblasts (CAFs) and inflammatory factors can normalize the TME by suppressing HH signaling. Furthermore, aberrant HH signaling activation is favorable to both the proliferation of cancer stem cells (CSCs) and the drug resistance of gastrointestinal tumors. This review discusses the current understanding of the role and mechanism of aberrant HH signaling activation in gastrointestinal carcinogenesis, the gastrointestinal TME, tumor immune tolerance and drug resistance and highlights the underlying therapeutic opportunities.

Hedging against Neuropathic Pain: Role of Hedgehog Signaling in Pathological Nerve Healing.

The peripheral nervous system has important regenerative capacities that regulate and restore peripheral nerve homeostasis. Following peripheral nerve injury, the nerve undergoes a highly regulated degeneration and regeneration process called Wallerian degeneration, where numerous cell populations interact to allow proper nerve healing. Recent studies have evidenced the prominent role of morphogenetic Hedgehog signaling pathway and its main effectors, Sonic Hedgehog (SHH) and Desert Hedgehog (DHH) in the regenerative drive following nerve injury. Furthermore, dysfunctional regeneration and/or dysfunctional Hedgehog signaling participate in the development of chronic neuropathic pain that sometimes accompanies nerve healing in the clinical context. Understanding the implications of this key signaling pathway could provide exciting new perspectives for future research on peripheral nerve healing.

Convergent pathological and ultrasound features in hereditary syndromic and non-syndromic minifascicular neuropathy related to DHH.

Minifascicular neuropathy (MN) is a rare, autosomal recessive disease with prominent structural changes of peripheral nerves. So far, it has been observed in females with a 46,XY karyotype and mutations of the Desert Hedgehog (DHH) gene, thus linking MN to gonadal dysgenesis (GD) and disorders of sex development (DSD). However, a 46,XX proband with normal female sex and gender development underwent clinical evaluations, nerve conduction studies and genetic screening for a severe motor-sensory neuropathy with a pathological phenotype that hinted at MN. Indeed, sural nerve biopsy revealed a profound disturbance of perineurium development with a thin and loose structure. High-resolution ultrasound (HRUS) also disclosed diffuse changes of nerve echotexture that visibly correlated with the pathological features. After extensive genetic testing, a novel homozygous DHH null mutation (p.Ser185*) was identified in the proband and in her sister, who was affected by a similar motor-sensory neuropathy, but was eventually found to be a 46,XY patient according to a late diagnosis of DSD with complete GD. DHH should therefore be considered as a possible cause of rare non-syndromic hereditary motor-sensory neuropathies, regardless of DSD. Furthermore, HRUS could effectively smooth the complex diagnostic workup as it demonstrated a high predictive power to detect MN, providing the same detailed correlations to the pathologic features of the nerve biopsy and Dhh-/- mice in both sisters. Hence, HRUS may assume a pivotal role in guiding molecular analysis in individuals with or without DSD.

Mouse Ptchd3 is a non-essential gene.

Mouse Ptchd3 (patched domain containing 3) was previously identified as a male germ-cell specific gene. The protein product of this gene has been found on the surface of mouse, rat and human sperm. Since Ptchd3 contains a conserved patched domain, we hypothesize that it functions as a membrane receptor for the hedgehog ligand. Herein, we used a Ptchd3 knockout mouse model to study its function in mouse development and spermatogenesis. We found that Ptchd3 knockout mice were born and lived normally. The fertility and sperm production of knockout males were not changed. Moreover, our data indicated that the expression levels of several hedgehog signaling genes were not affected in mutant testis. Taken together, these findings demonstrate that Ptchd3 is a non-essential gene in mouse development and spermatogenesis.

Desert hedgehog-primary cilia cross talk shapes mitral valve tissue by organizing smooth muscle actin.

Non-syndromic mitral valve prolapse (MVP) is the most common heart valve disease affecting 2.4% of the population. Recent studies have identified genetic defects in primary cilia as causative to MVP, although the mechanism of their action is currently unknown. Using a series of gene inactivation approaches, we define a paracrine mechanism by which endocardially-expressed Desert Hedgehog (DHH) activates primary cilia signaling on neighboring valve interstitial cells. High-resolution imaging and functional assays show that DHH de-represses smoothened at the primary cilia, resulting in kinase activation of RAC1 through the RAC1-GEF, TIAM1. Activation of this non-canonical hedgehog pathway stimulates α-smooth actin organization and ECM remodeling. Genetic or pharmacological perturbation of this pathway results in enlarged valves that progress to a myxomatous phenotype, similar to valves seen in MVP patients. These data identify a potential molecular origin for MVP as well as establish a paracrine DHH-primary cilium cross-talk mechanism that is likely applicable across developmental tissue types.

Next-Generation Sequencing Reveals Novel Genetic Variants (SRY, DMRT1, NR5A1, DHH, DHX37) in Adults With 46,XY DSD.

CONTEXT: The genetic basis of human sex development is slowly being elucidated, and >40 different genetic causes of differences (or disorders) of sex development (DSDs) have now been reported. However, reaching a specific diagnosis using traditional approaches can be difficult, especially in adults where limited biochemical data may be available. OBJECTIVE: We used a targeted next-generation sequencing approach to analyze known and candidate genes for DSDs in individuals with no specific molecular diagnosis. PARTICIPANTS AND DESIGN: We studied 52 adult 46,XY women attending a single-center adult service, who were part of a larger cohort of 400 individuals. Classic conditions such as17ß-hydroxysteroid dehydrogenase deficiency type 3, 5α-reductase deficiency type 2, and androgen insensitivity syndrome were excluded. The study cohort had broad working diagnoses of complete gonadal dysgenesis (CGD) (n = 27) and partially virilized 46,XY DSD (pvDSD) (n = 25), a group that included partial gonadal dysgenesis and those with a broad "partial androgen insensitivity syndrome" label. Targeted sequencing of 180 genes was undertaken. RESULTS: Overall, a likely genetic cause was found in 16 of 52 (30.8%) individuals (22.2% CGD, 40.0% pvDSD). Pathogenic variants were found in sex-determining region Y (SRY; n = 3), doublesex and mab-3-related transcription factor 1 (DMRT1; n = 1), NR5A1/steroidogenic factor-1 (SF-1) (n = 1), and desert hedgehog (DHH; n = 1) in the CGD group, and in NR5A1 (n = 5), DHH (n = 1), and DEAH-box helicase 37 (DHX37; n = 4) in the pvDSD group. CONCLUSIONS: Reaching a specific diagnosis can have clinical implications and provides insight into the role of these proteins in sex development. Next-generation sequencing approaches are invaluable, especially in adult populations or where diagnostic biochemistry is not possible.

46,XY complete gonadal dysgenesis in a familial case with a rare mutation in the desert hedgehog (DHH) gene.

PURPOSE: Disorders of sex development (DSD) have been linked to gene defects that lead to gonadal dysgenesis. Herein, we aimed to identify the genetic cause of gonadal dysgenesis in a patient with primary amenorrhoea tracing it to a phenotypic female carrying a 46,XY karyotype of a consanguineous family. METHODS AND RESULTS: Whole exome sequencing (WES) was performed and revealed in homozygosity the rare and only once reported p.Arg164Pro missense mutation in exon 2 of the desert hedgehog (DHH) gene. Sanger sequencing was used to validate this candidate variant both in the patient, the parents, and two siblings. Both brother and sister of the index patient were found negative for the p.Arg164Pro mutation, while the consanguineous parents were found to carry the mutation in the heterozygous state. Neither the parents nor the unaffected siblings showed any reproductive malformations. CONCLUSIONS: Defects in the DHH gene have been reported as a very rare cause of DSD, and this report increases the number of 46,XY gonadal dysgenesis cases. Additionally, the present study highlights the importance of genetic validation of patients with DSD, since this is likely to alleviate the considerable psychological distress experienced by both the patient and the parents.

Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development.

BACKGROUND: Desert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many of these variants were classified as variants of uncertain significance due to their heterozygosity or associated milder phenotype. To assess variant pathogenicity and to refine the spectrum of DSDs associated with this gene, we have carried out the first reported functional testing of DHH gene variant activity. METHODS: A cell co-culture method was used to assess DHH variant induction of Hedgehog signalling in cultured Leydig cells. Protein expression and subcellular localisation were also assessed for DHH variants using western blot and immunofluorescence. RESULTS: Our co-culture method provided a robust read-out of DHH gene variant activity, which correlated closely with patient phenotype severity. While biallelic DHH variants from patients with gonadal dysgenesis showed significant loss of activity, variants found as heterozygous in patients with milder phenotypes had no loss of activity when tested with a wild type allele. Taking these functional results into account improved clinical interpretation. CONCLUSION: Our findings suggest heterozygous DHH gene variants are unlikely to cause DSD, reaffirming that DHH is an autosomal recessive cause of 46,XY gonadal dysgenesis. Functional characterisation of novel DHH variants improves variant interpretation, leading to greater confidence in patient reporting and clinical management.

A familial syndrome of hypothalamic hamartomas, polydactyly, and SMO mutations: a clinical report of 2 cases.

Hypothalamic hamartomas are benign tumors known to cause gelastic or dacrystic seizures, precocious puberty, developmental delay, and medically refractory epilepsy. These tumors are most often sporadic but rarely can be associated with Pallister-Hall syndrome, an autosomal dominant familial syndrome caused by truncation of glioblastoma transcription factor 3, a downstream effector in the sonic hedgehog pathway. In this clinical report, the authors describe two brothers with a different familial syndrome. To the best of the authors' knowledge, this is the first report in the literature describing a familial syndrome caused by germline mutations in the Smoothened (SMO) gene and the first familial syndrome associated with hypothalamic hamartomas other than Pallister-Hall syndrome. The authors discuss the endoscopic endonasal biopsy and subtotal resection of a large hypothalamic hamartoma in one of the patients as well as the histopathological findings encountered. Integral to this discussion is the understanding of the hedgehog pathway; therefore, the underpinnings of this pathway and its clinical associations to date are also reviewed.

In vitro functional characterization of the novel DHH mutations p.(Asn337Lysfs*24) and p.(Glu212Lys) associated with gonadal dysgenesis.

In humans, mutations of Desert Hedgehog gene (DHH) have been described in patients with 46,XY gonadal dysgenesis (GD), associated or not with polyneuropathy. In this study, we describe two patients diagnosed with GD, both harboring novel DHH compound heterozygous mutations p.[Tyr176*];[Asn337Lysfs*24] and p.[Tyr176*];[Glu212Lys]. To investigate the functional consequences of p.(Asn337Lysfs*24) and p.(Glu212Lys) mutations, located within the C-terminal part of DHh on auto-processing, we performed in vitro cleavage assays of these proteins in comparison with Drosophila melanogaster Hedgehog (Hh). We found that p.(Glu212Lys) mutation retained 50% of its activity and led to a partially abolished DHh auto-processing. In contrast, p.(Asn337Lysfs*24) mutation resulted in a complete absence of auto-proteolysis. Furthermore, we found a different auto-processing profile between Drosophila Hh and human DHh, which suggests differences in the processing mechanism between the two species. Review of the literature shows that proven polyneuropathy and GD is associated with complete disruption of DHh-N, whereas disruption of the DHh auto-processing is only described with GD. We propose a model that may explain the differences between Schwann and Leydig cell development by autocrine versus paracrine DHh signaling. To our knowledge, this is the first study investigating the effect of DHH mutations on DHh in vitro auto-processing.

A novel, homozygous mutation in desert hedgehog (DHH) in a 46, XY patient with dysgenetic testes presenting with primary amenorrhoea: a case report.

BACKGROUND: Desert hedgehog (DHH) mutations have been described in only a limited number of individuals with 46, XY disorders of sex development (DSD) presenting as either partial or complete gonadal dysgenesis. Gonadal tumours and peripheral neuropathy have been associated with DHH mutations. Herein we report a novel, homozygous mutation of DHH identified through a targeted, massively parallel sequencing (MPS) DSD panel, in a patient presenting with partial gonadal dysgenesis. This novel mutation is two amino acids away from a previously described mutation in a patient who presented with complete gonadal dysgenesis. Adding to the complexity of work-up, our patient also expressed gender identity concern. CASE PRESENTATION: A 14-year-old, phenotypic female presented with primary amenorrhoea and absent secondary sex characteristics. Investigations revealed elevated gonadotrophins with low oestradiol, testosterone of 0.6 nmol/L and a 46, XY karyotype. Müllerian structures were not seen on pelvic ultrasound or laparoscopically and gonadal biopsies demonstrated dysgenetic testes without neoplasia (partial gonadal dysgenesis). The patient expressed gender identity confusion upon initial notification of investigation findings. Formal psychiatric evaluation excluded gender dysphoria. Genetic analysis was performed using a targeted, MPS DSD panel of 64 diagnostic and 927 research candidate genes. This identified a novel, homozygous mutation in exon 2 of DHH (DHH:NM_021044:exon2:c.G491C:p.R164P). With this finding our patient was screened for the possibility of peripheral neuropathy which was not evident clinically nor on investigation. She was commenced on oestrogen for pubertal induction. CONCLUSION: The evaluation of patients with DSD is associated with considerable psychological distress. Targeted MPS enables an affordable and efficient method for diagnosis of 46, XY DSD cases. Identifying a genetic diagnosis may inform clinical management and in this case directed screening for peripheral neuropathy. In addition to the structural location of the mutation other interacting factors may influence phenotypic expression in homozygous DHH mutations.