Expanding the phenotypic and genotypic spectrum of GGPS1 related congenital muscular dystrophy.

Congenital muscular dystrophies are a group of progressive disorders with wide range of symptoms associated with diverse cellular mechanisms. Recently, biallelic variants in GGPS1 were linked to a distinct autosomal recessive form of muscular dystrophy associated with hearing loss and ovarian insufficiency. In this report, we present a case of a young patient with a homozygous variant in GGPS1. The patient presented with only proximal muscle weakness, and elevated liver transaminases with spared hearing function. The hepatic involvement in this patient caused by a novel deleterious variant in the gene extends the phenotypic and genotypic spectrum of GGPS1 related muscular dystrophy.

MYH1 is a candidate gene for recurrent rhabdomyolysis in humans.

Rhabdomyolysis is a serious medical condition characterized by muscle injury, and there are recognized genetic causes especially in recurrent forms. The majority of these cases, however, remain unexplained. Here, we describe a patient with recurrent rhabdomyolysis in whom extensive clinical testing failed to identify a likely etiology. Whole-exome sequencing revealed a novel missense variant in MYH1, which encodes a major adult muscle fiber protein. Structural biology analysis revealed that the mutated residue is extremely well conserved and is located in the actin binding cleft. Furthermore, immediately adjacent mutations in that cleft in other myosins are pathogenic in humans. Our results are consistent with the finding that MYH1 is mutated in rhabdomyolysis in horses and suggest that this gene should be investigated in cases with recurrent rhabdomyolysis.

Angiocentric glioma of brainstem.

Angiocentric glioma is a rare brain tumor commonly found in frontal or temporal lobes. It has a benign course, and surgical resection can be curative. Brainstem location is extremely rare, with only six cases reported so far in the literature. In the present study, the seventh case of brainstem angiocentric glioma has been reported, and its course in comparison with supratentorial location and the role of molecular diagnosis has been discussed.

Infantile atypical subependymal giant cell astrocytoma.

Subependymal giant cell astrocytoma is a benign WHO grade I intraventricular tumor arise in patients with tuberous sclerosis complex. Previous reported described histopathological predictors of more aggressive forms, terms atypical SEGA in infantile age group. Other reports showed possible transformation of SEGA into glioblastoma, or misdiagnosis as glioblastoma due to the presence of atypical histopathological features. Here, we report a case of an infant who presented with right frontal extraventricular SEGA and underwent craniotomy with complete resection. Eight months later, he presented with fast recurrence in same location with midline shift and subfalcine herniation. Histopathological description showed high grade features including Ki labeling index of 60%, atypical mitotic figures, cellular plemorphism and necrosis. We also discussed the possible presence of different entity (termed atypical SEGA) which may have more aggressive clinical course, with literature review of predictors of SEGA aggressiveness and possible transformation/misdiagnosis as glioblastoma.

Central Nervous System Brucellosis Granuloma and White Matter Disease in Immunocompromised Patient.

Brucellosis is a multisystem zoonotic disease. We report an unusual case of neurobrucellosis with seizures in an immunocompromised patient in Saudi Arabia who underwent renal transplantation. Magnetic resonance imaging of the brain showed diffuse white matter lesions. Serum and cerebrospinal fluid were positive for Brucella sp. Granuloma was detected in a brain biopsy specimen.

Mutations in NALCN cause an autosomal-recessive syndrome with severe hypotonia, speech impairment, and cognitive delay.

Sodium leak channel, nonselective (NALCN) is a voltage-independent and cation-nonselective channel that is mainly responsible for the leaky sodium transport across neuronal membranes and controls neuronal excitability. Although NALCN variants have been conflictingly reported to be in linkage disequilibrium with schizophrenia and bipolar disorder, to our knowledge, no mutations have been reported to date for any inherited disorders. Using linkage, SNP-based homozygosity mapping, targeted sequencing, and confirmatory exome sequencing, we identified two mutations, one missense and one nonsense, in NALCN in two unrelated families. The mutations cause an autosomal-recessive syndrome characterized by subtle facial dysmorphism, variable degrees of hypotonia, speech impairment, chronic constipation, and intellectual disability. Furthermore, one of the families pursued preimplantation genetic diagnosis on the basis of the results from this study, and the mother recently delivered healthy twins, a boy and a girl, with no symptoms of hypotonia, which was present in all the affected children at birth. Hence, the two families we describe here represent instances of loss of function in human NALCN.

Classical V600E and other non-hotspot BRAF mutations in adult differentiated thyroid cancer.

BACKGROUND: BRAF is the most frequently mutated gene in differentiated thyroid cancer (DTC). Previous studies on DTC have well documented high rates of the BRAF (V600E) mutation in patients of mixed ages. Previous studies either included a mix of pediatric and adult patients or pediatric patients only. However, the prevalence of hotspot and non-hotspot BRAF mutations and its significance in pure adult DTCs is not yet well determined. In this study we determine the frequency of this classical BRAF mutation and other rare BRAF mutations in pure adult DTCs. METHODS: A total of 204 adult DTC samples (Age >18 years) were analyzed for mutations in exon 15 of the BRAF gene by performing polymerase chain reaction (PCR) amplification of tumor genomic DNAs and direct sequencing of amplicons using Sanger sequencing. Obtained results were correlated to clinical and pathological characteristics of DTCs. Statistical analyses were performed using SPSS (The Statistical Package for Social Sciences) version 20 software. RESULTS: Overall, BRAF mutations were identified in 48.5 % (99/204) of adult DTCs. Three rare non-hotspot mutations (T599I, T599dup and K601E) were detected in four tumor samples (2 %). One (K601E) of these non-hotspot mutations occurred in conventional papillary thyroid cancer (CPTC) and other three (T599I, T599dup and K601E) were found in follicular variant PTC. We found significant association between BRAF (V600E) mutation and age (P < 0.0001), extrathyroidal invasion (P = 0.017), lymph node metastasis (P = 0.038) and TNM stage III/IV (P = 0.001). CONCLUSIONS: Our study is the first to report BRAF mutations in a pure adult sample of DTCs of Saudi Arabian ethnicity. Our results show a high rate and a strong prognostic role of the classical BRAF (V600E) mutation and also suggest a common occurrence of non-hot spot mutations in adult DTC from this highly inbred population.

Comparison of differentiated thyroid cancer in children and adolescents (≤20 years) with young adults.

CONTEXT: Age is a major prognostic factor in differentiated thyroid cancer (DTC). It is not clear if paediatric DTC has a different histopathological profile and outcome than DTC in adult patients <45 years of age. OBJECTIVE: To assess whether DTC in children and adolescents differs from young age group by comparing paediatric DTC (age ≤ 20) with DTC in patients >20 to <45 years of age. PATIENTS AND METHODS: We studied all cases of paediatric DTC seen during the period 1998-2011. We compared this group with a large sample of 213 consecutive adult patients in the age group >20 to <45 years seen during the period 1998-1999 in terms of their pathological features, extent of the disease and long-term outcome. Both groups were managed by the same team at a single institution. RESULTS: A total of 310 DTC were studied including 97 paediatric patients [median age 17 years (range, 8-20)] and 213 young adult patients [median age 33 years (range, 20·5-44·9)]. There was no difference in gender distribution, tumour subtypes, size and tumour multifocality, but there was a significantly higher rate of extrathyroidal extension [40/75 (53·3%) vs 81/213 (38·0%), P = 0·03], lymph node [57/73 (78%) vs 102/183 (55·7%), P < 0·0001] and distant metastases [16/97 (16·5%) vs 8/213 (3·8%), P < 0·0001] in the paediatric than the adult groups. Kaplan-Meier analysis showed a higher risk of persistent/recurrent disease in the paediatric group than adults (log-rank test 0·03). However, there was no mortality secondary to DTC in both groups. CONCLUSION: Paediatric DTC is distinct from DTC in the young adults (age >20 to <45 years). It is characterized by a higher rate of extrathyroidal extension, lymph node and distant metastases and a higher risk of persistent/recurrent DTC.

ISCA2 mutation causes infantile neurodegenerative mitochondrial disorder.

BACKGROUND: There are numerous nuclear genes that cause mitochondrial disorders and clinically and genetically heterogeneous disorders whose aetiology often remains unsolved. In this study, we aim to investigate an autosomal recessive syndrome causing leukodystrophy and neuroregression. We studied six patients from five unrelated consanguineous families. METHODS: Patients underwent full neurological, radiological, genetic, metabolic and dysmorphological examinations. Exome sequencing coupled with autozygosity mapping, Sanger sequencing, microsatellite haplotyping, standard and molecular karyotyping and whole mitochondrial DNA sequencing were used to identify the genetic cause of the syndrome. Immunohistochemistry, transmission electron microscopy, confocal microscopy, dipstick assays, quantitative PCR, reverse transcription PCR and quantitative reverse transcription PCR were performed on different tissue samples from the patients. RESULTS: We identified a homoallelic missense founder mutation in ISCA2 leading to mitochondrial depletion and reduced complex I activity as well as decreased ISCA2, ISCA1 and IBA57 expression in fibroblasts. MRI indicated similar white matter abnormalities in the patients. Histological examination of the skeletal muscle showed mild to moderate variation in myofibre size and the presence of many randomly distributed atrophic fibres. CONCLUSIONS: Our data demonstrate that ISCA2 deficiency leads to a hereditary mitochondrial neurodegenerative white matter disease in infancy.

LncRNA GAS8-AS1 dinucleotide genetic variantn.713A>G, n.714T>C is associated with early-stage disease, lymph node, and distant metastasis in differentiated thyroid cancer.

PURPOSE: Long noncoding RNAs (lncRNAs) play an essential role in the epigenetic regulation of various key genes involved in vital cellular functions. A somatic dinucleotide mutation in the lncRNA GAS8-AS1 was reported in Chinese papillary thyroid cancer. However, GAS8-AS1 dinucleotide alteration and its impact have never been explored in differentiated thyroid cancers and other populations. METHODS: We extracted genomic DNA from 265 DTCs and 97 normal healthy subjects, PCR amplified and Sanger sequenced to examine the GAS8-AS1 dinucleotide alteration. Calculated genotype/allele frequency to test Hardy-Weinberg Equilibrium (HWE) and performed a genetic model of inheritance to determine its association with DTC risk. Correlated the GAS8-AS1 dinucleotide variant distribution with clinical characteristics to find the association. Predicted GAS8-AS1 RNA secondary structure for wild type and variant using RemuRNA and RNAfold to assess the conformational changes. RESULTS: GAS8-AS1 dinucleotide alteration (n.713A > G, rs55742939; n.714T > C, rs61118444) identified in DTCs is a germline variant not somatic. The GAS8-AS1 genotype and allele frequency significantly deviated for HWE in DTCs (χ2 = 37.954; p = 0.0001) though not associated with its risk. Dinucleotide variant distribution was remarkably associated with early-stage disease (p = 0.002), lymph node (p = 0.01), and distant metastasis (p = 0.01) in DTCs. The GAS8-AS1 bearing dinucleotide variant markedly showed conformational change compared to that of its wild type. CONCLUSIONS: These findings indicate that GAS8-AS1 is genetically deregulated and implicated in several stages of DTC tumorigenesis suggesting it could be a promising prognostic biomarker in DTCs.

EPAS1-related pheochromocytoma/paraganglioma.

In 2012, somatic EPAS1 pathogenic variants were found to cause a triad of pheochromocytoma/paragangliomas (PPGLs), polycythemia, and somatostatinoma. Since then, a limited number of studies on this subject have been reported, and data on the long-term outcome of metastatic disease are not available on this rare syndrome. We comprehensively reviewed EPAS1-related PPGL and describe an unusual patient who has been living with an EPAS1-related metastatic PPGL for 47 years. The results of this work show that EPAS1 pathogenic variants are rare, more in females and patients without pathogenic variants in other PPGL susceptibility genes. PPGLs are the most common manifestation followed by polycythemia and somatostatinoma. The EPAS1 pathogenic variants are often postzygotic, and the timing of their acquirement during embryonic development seems to correlate with the number and timing of development of the disease manifestations. Although recurrent and multifocal disease is common in EPAS1-related PPGL, distant metastases are uncommon and usually indolent. This is illustrated by a case of a man who was diagnosed at the age of 9 years and is currently 56 years old, alive, and well for 47 years with these metastases. He was found to have a somatic EPAS1 pathogenic variant (c.1592C>A, p.Pro531His) in bilateral pheochomocytoma and a pancreatic NET (somatostatinoma) but not in genomic DNA isolated from peripheral leukocytes. This and previous reports suggest that distant metastases are uncommon and less aggressive in EPAS1-related PPGLs compared to those found in other hereditary PPGLs.

Clinical and biochemical features associated with BCS1L mutation.

Our study describes a novel phenotype in a series of nine Saudi patients with lactic acidosis, from four consanguineous families three of which are related. Detailed genetic studies including linkage, homozygosity mapping and targeted sequencing identified a causative mutation in the BCS1L gene. All affected members of the families have an identical mutation in this gene, mutations of which are recognized causes of Björnstad syndrome, GRACILE syndrome and a syndrome of neonatal tubulopathy, encephalopathy, and liver failure (MIM 606104) leading to isolated mitochondrial respiratory chain complex III deficiency. Here we report the appearance of a novel behavioral (five patients) and psychiatric (two patients) phenotype associated with a p.Gly129Arg BCS1L mutation, differing from the phenotype in a previously reported singleton patient with this mutation. The psychiatric symptoms emanated after childhood, initially as hypomania later evolving into intermittent psychosis. Neuroradiological findings included subtle white matter abnormalities, whilst muscle histopathology and respiratory chain studies confirmed respiratory chain dysfunction. The variable neuro-psychiatric manifestations and cortical visual dysfunction are most unusual and not reported associated with other BCS1L mutations. This report emphasizes the clinical heterogeneity associated with the mutation in BCS1L gene, even within the same family and we recommend that defects in this gene should be considered in the differential diagnosis of lactic acidosis with variable involvement of different organs.

Thyroid Cancer, Neuroendocrine Tumor, Adrenal Adenoma, and Other Tumors in a Patient With a Germline PMS1 Mutation.

Context: Multiple tumors in the same patient suggest a genetic predisposition. Here, we report a patient who presented with several unusual types of malignant and benign tumors, presumably due to a pathogenic germline PMS1 mutation. Case: A 69-year-old woman presented with a 2-year history of abdominal pain and diarrhea. A computed tomography scan of the abdomen revealed a gastrointestinal neuroendocrine tumor (GiNET) with liver metastases and a nonfunctional benign adrenal adenoma. Bilateral large lung nodules were thought to be also metastases from the GiNET but turned out to be differentiated thyroid cancer metastases, which later progressed to anaplastic thyroid cancer (ATC) and led to the patient's demise. A right sphenoid wing meningioma causing partial hypopituitarism was diagnosed during her evaluation. A mammogram and a breast ultrasound revealed a 0.3-cm left breast nodule. Due to the multiplicity of her tumors, whole exome sequencing was performed. This revealed a previously described PMS1 deletion mutation causing a frameshift and truncation (NM_000534c.1258delC, p.His420Ilefs*22) but no other pathogenic variant in other cancer genes. DNA isolated from the ATC tumor tissue showed loss of heterozygosity of the same mutation, highly suggestive of its pathogenic role in thyroid cancer and presumably other tumors. Conclusion: This case reports several tumors including thyroid cancer, GiNET, adrenal adenoma, meningioma, and breast nodule, likely due to the PMS1 mutation found in this patient.

Molecular Genetics of Diffuse Sclerosing Papillary Thyroid Cancer.

CONTEXT: Diffuse sclerosing papillary thyroid cancer (DSPTC) is rare, with limited data on its molecular genetics. OBJECTIVE: We studied the molecular genetics of a cohort of DSPTC. METHODS: DNA was isolated from paraffin blocks of 22 patients with DSPTC (15 females, 7 males, median age 18 years, range 8-81). We performed polymerase chain reaction-based Sanger sequencing and a next-generation sequencing (NGS) gene panel to characterize the genomic landscape of these tumors. We classified genetic alterations to definitely or probably pathogenic. Definitely pathogenic are genetic alterations that are well known to be associated with PTC (e.g., BRAFV600E). Probably pathogenic are other alterations in genes that were reported in The Cancer Genome Atlas or the poorly differentiated and anaplastic thyroid cancer datasets. RESULTS: Three tumors were tested only by Sanger sequencing and were negative for BRAFV600E, HRAS, KRAS, NRAS, TERT promoter, PTEN, and PIK3CA mutations. The other 19 tumors tested by NGS showed definitely pathogenic alterations in 10 patients (52.6%): 2/19 (10.5%) BRAFV600E, 5/19 (26.3%) CCDC6-RET (RET/PTC1), 1/19 (5.3%) NCOA4-RET (RET/PTC3), 1/19 (5.3%) STRN-ALK fusion, and 2/19 (10.6%) TP53 mutations. Probably pathogenic alterations occurred in 13/19 tumors (68.4%) and included variants in POLE (31.6%), CDKN2A (26%), NF1 (21%), BRCA2 (15.8%), SETD2 (5.3%), ATM (5.3%), FLT3 (5.3%), and ROS1 (5.3%). In 1 patient, the gene panel showed no alterations. No mutations were found in the RAS, PTEN, PIK3CA, or TERT promoter in all patients. There was no clear genotype/phenotype correlation. CONCLUSION: In DSPTC, fusion genes are common, BRAFV600E is rare, and other usual point mutations are absent. Pathogenic and likely pathogenic variants in POLE, NF1, CDKN2A, BRCA2, TP53, SETD2, ATM, FLT3, and ROS1 occur in about two-thirds of DTPTC.

The impact of thyroid imaging reporting and data system on the management of Bethesda III thyroid nodules.

Objectives: Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is a heterogeneous category of fine needle aspiration cytology (FNAC); the management of this condition remains controversial. The clinical significance of such patients relies on the exclusion of malignancy. In this study, we aimed to determine the validity of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) (2017) for predicting malignancy in this specific category of patients. Methods: In this study, we analysed a cohort of patients from our previous retrospective study. This four-year retrospective cohort study included all cases undergoing surgery with a cytological diagnosis of AUS/FLUS. We enrolled 110 cases with documented final histopathological diagnoses and ultrasound examinations. Results: The study included 83 females (75.5%) and 27 males (24.5%). The overall risk of malignancy (ROM) for AUS/FLUS thyroid nodules was 47.3%. The ROMs of TI-RADS 3 (TR3), TI-RADS 4 (TR4), and TI-RADS 5 (TR5) were 43.5%, 49.4% and 40%, respectively. There was no significant association between TI-RADS and final pathological analysis. Conclusions: Repeated FNAC with initial AUS/FLUS nodules is crucial. Our findings showed that ACR TI-RADS did not contribute to the cancer risk stratification of AUS/FLUS nodules. A large prospective multi-institutional study is now required to determine the validity of ACR TI-RADS and whether other adjunct clinical, cytological, molecular, or biochemical tools could facilitate the management of patients with these heterogeneous nodules.

An aggressive cabergoline-resistant, temozolomide-responsive macroprolactinoma due to a germline SDHB pathogenic variant in the absence of paraganglioma or pheochromocytoma.

Context: Germline succinate dehydrogenase subunit B (SDHB) pathogenic variants are characteristic of familial paraganglioma (PGL) syndrome type 4. This syndrome frequently presents with abdominal PGL and has high tendency for locally aggressive behavior and distant metastasis. The vast majority of pituitary adenomas (PAs) are sporadic. However, PAs can be part of a number of familial tumor syndromes such as multiple endocrine neoplasia type 1 (MEN 1) or more rarely in association with pheochromocytoma and PGL (referred to as 3P syndrome). Only a limited number of PAs in association with SDHB-related PGL has been reported and the vast majority occurred subsequently or simultaneously with pheochromocytoma/PGL (collectively abbreviated as PPGL). In this report, we describe a young patient who had a giant pituitary macroprolactinoma resistant to large doses of cabergoline (CBG) and external beam radiotherapy (XRT). The patient did not have personal history of PPGL but was found to carry a germline SDHB pathogenic variant. Case report: A 38-year-old woman presented with headache, visual disturbances and galactorrhea and was found to have a 34-mm macroprolactinoma. She was treated with CBG 3-4 mg per week but PA continued to grow and caused significant cranial pressure symptoms. She underwent two transsphenoidal surgeries with rapid tumor recurrence after each one. She received XRT but PA continued to grow. She was finally treated with temozolomide with excellent response. Whole exome and subsequent Sanger sequencing confirmed that she has a pathogenic monoallelic SDHB mutation (NM_003000:c.C343T, p.R115*). PA tissue showed loss of heterozygosity for the same mutation and absent SDHB immunostaining confirming the pathogenic role of this SDHB mutation. Conclusion: Germline SDHB mutations can rarely cause PA in the absence of PPGL. They should be considered as a possible cause of aggressiveness and resistance to dopamine agonists in similar cases.

A molecular study of pediatric pilomyxoid and pilocytic astrocytomas: Genome-wide copy number screening, retrospective analysis of clinicopathological features and long-term clinical outcome.

Background: Pilocytic Astrocytoma (PA) is the most common pediatric brain tumors. PAs are slow-growing tumors with high survival rates. However, a distinct subgroup of tumors defined as pilomyxoid astrocytoma (PMA) presents unique histological characteristics and have more aggressive clinical course. The studies on genetics of PMA are scarce. Methods: In this study, we report one of the largest cohort of pediatric patients with pilomyxoid (PMA) and pilocytic astrocytomas (PA) in Saudi population providing a comprehensive clinical picture, retrospective analysis with long-term follow-up, genome-wide copy number changes, and clinical outcome of these pediatric tumors. We examined and compared genome-wide copy number aberrations (CNAs) and the clinical outcome of the patients with PA and PMA. Results: The median progression free survival for the whole cohort was 156 months and it was 111 months for the PMA, however, not statistically significantly different between the groups (log-rank test, P = 0.726). We have identified 41 CNAs (34 gains and 7 losses) in all tested patients. Our study yielded the previously reported KIAA1549-BRAF Fusion gene in over 88% of the tested patients (89% and 80% in PMA and PA, respectively). Besides the fusion gene, twelve patients had additional genomic CNAs. Furthermore, pathway and gene network analyses of genes in the fusion region revealed alterations in retinoic acid mediated apoptosis and MAPK signaling pathways and key hub genes that may potentially be involved in tumor growth and progression, including BRAF, LUC7L2, MKRN1, RICTOR, TP53, HIPK2, HNF4A, POU5F, and SOX4. Conclusion: Our study is the first report of a large cohort of patients with PMA and PA in the Saudi population that provides detailed clinical features, genomic copy number changes, and outcome of these pediatric tumors and may help better diagnosis and characterization of PMA.

Fumarate Hydratase is a Novel Gene for Familial Non-Medullary Thyroid Cancer.

CONTEXT: The majority of cases of epithelial cell-derived thyroid cancer are sporadic. Familial non-medullary thyroid cancer (FNMTC) occurs in about 5% to 9% of cases, either as a part of known syndromes such as Cowden syndrome or in the form of familial clustering of 2 or more affected family members. Hereditary leiomyoma and renal cell cancer (HLRCC) syndrome is a rare familial cancer syndrome. The underlying etiology is heterozygous germline mutations of the fumarate hydratase (FH) gene. In addition to extensive uterine and skin leiomyomas and RCC, other tumors may arise in this syndrome. However, thyroid cancer has never been described as part of HLRCC. Here, we describe a woman who presented with an aggressive poorly differentiated thyroid cancer (PDTC) and was found to have HLRCC syndrome because of a novel heterozygous germline FH mutation. RESULTS: A 43-year-old woman presented with a large lower neck mass that was found to be PDTC. During her evaluation, she was found to have extensive uterine leiomyomatosis and bilateral adrenal nodules. Whole exome and subsequent Sanger sequencing of leucocyte DNA revealed a novel monoallelic nonsense FH mutation (c.760C>T, p.Q254*). Sequencing of the thyroid tumor tissue showed a biallelic loss at the same mutation site (loss of heterozygosity) and immunohistochemistry of the PDTC showed loss of FH staining in the tumor tissue, indicating the pathogenic role of this mutation in the development of PDTC in this patient. CONCLUSION: Thyroid cancer is a novel feature of the FH-related HLRCC syndrome. This syndrome can be added to the rare genetic causes of syndromic FNMTC.

Papillary Thyroid Cancer and a TERT Promotor Mutation-positive Paraganglioma in a Patient With a Germline SDHB Mutation.

Purpose: About 40% of paragangliomas (PGL) are due to germline mutations in one of several susceptibility genes. These genes rarely predispose to other non-PGL tumors. Here, we describe and functionally characterize a germline SDHB mutation in a patient who developed a BRAF V600E mutation-positive papillary thyroid cancer (PTC) and a TERT promotor mutation-positive PGL. Experimental design: A 28-year-old asymptomatic man was discovered incidentally to have a large left-sided mid-abdominal PGL and PTC. He underwent resection of the PGL and total thyroidectomy and neck dissection followed by I-131 adjuvant therapy for PTC. The histopathology revealed a high-grade PGL and a tall cell-variant PTC with lymph node metastases (T1b N1b M0). He soon developed PGL spinal metastases that have been rapidly progressing and is currently being treated with Lu177-dotatate therapy. Family screening revealed a positive SDHB mutation in the mother, a son, and a brother. Results: In addition to the heterozygous SDHB germline mutation (c.688C>T, p.Arg230Cys), molecular analysis revealed a somatic TERT promotor mutation (C228T) in PGL (negative in PTC) and a somatic BRAF V600E mutation in PTC (negative in PGL). Functional studies showed a higher proliferation rate in the mutant compared with the wild-type SDHB. Conclusion: Germline SDHB mutations rarely occur in patients with PTC and may contribute to its aggressiveness. Somatic TERT promotor mutations rarely occur in PGL and contribute to its aggressiveness and metastatic potential.

Case Report: Severe Gonadal Dysgenesis Causing 46,XY Disorder of Sex Development Due to a Novel NR5A1 Variant.

Mutations in the nuclear receptor subfamily 5 group A member 1 (NR5A1) are the underlying cause of 10-20% of 46,XY disorders of sex development (DSDs). We describe a young girl with 46,XY DSD due to a unique novel mutation of the NR5A1 gene. An 11-year-old subject, raised as a female, was noticed to have clitromegly. She looked otherwise normal. However, her evaluation revealed a 46,XY karyotype, moderate clitromegly but otherwise normal female external genitalia, undescended atrophied testes, rudimentary uterus, no ovaries, and lack of breast development. Serum testosterone and estradiol were low, and gonadotropins were elevated. Adrenocortical function was normal. DNA was isolated from the peripheral leucocytes and used for whole exome sequencing. The results were confirmed by Sanger sequencing. We identified a novel mutation in NR5A1 changing the second nucleotide of the translation initiation codon (ATG>ACG) and resulting in a change of the first amino acid, methionine to threonine (p.Met1The). This led to severe gonadal dysgenesis with deficiency of testosterone and anti-Müllerian hormone (AMH) secretion. Lack of the former led to the development of female external genitalia, and lack of the latter allowed the Müllerian duct to develop into the uterus and the upper vagina. The patient has a female gender identity. Bilateral orchidectomy was performed and showed severely atrophic testes. Estrogen/progesterone therapy was initiated with excellent breast development and normal cyclical menses. In summary, we describe a severely affected case of 46,XY DSD due to a novel NR5A1 mutation involving the initiation codon that fully explains the clinical phenotype in this subject.