RESUMEN
An optimal Golgi transport system is important for mammalian cells. The adenosine diphosphate (ADP) ribosylation factors (ARF) are key proteins for regulating cargo sorting at the Golgi network. In this family, ARF3 mainly works at the trans-Golgi network (TGN), and no ARF3-related phenotypes have yet been described in humans. We here report the clinical and genetic evaluations of two unrelated children with de novo pathogenic variants in the ARF3 gene: c.200A > T (p.Asp67Val) and c.296G > T (p.Arg99Leu). Although the affected individuals presented commonly with developmental delay, epilepsy and brain abnormalities, there were differences in severity, clinical course and brain lesions. In vitro subcellular localization assays revealed that the p.Arg99Leu mutant localized to Golgi apparatus, similar to the wild-type, whereas the p.Asp67Val mutant tended to show a disperse cytosolic pattern together with abnormally dispersed Golgi localization, similar to that observed in a known dominant negative variant (p.Thr31Asn). Pull-down assays revealed that the p.Asp67Val had a loss-of-function effect and the p.Arg99Leu variant had increased binding of the adaptor protein, Golgi-localized, γ-adaptin ear-containing, ARF-binding protein 1 (GGA1), supporting the gain of function. Furthermore, in vivo studies revealed that p.Asp67Val transfection led to lethality in flies. In contrast, flies expressing p.Arg99Leu had abnormal rough eye, as observed in the gain-of-function variant p.Gln71Leu. These data indicate that two ARF3 variants, the possibly loss-of-function p.Asp67Val and the gain-of-function p.Arg99Leu, both impair the Golgi transport system. Therefore, it may not be unreasonable that they showed different clinical features like diffuse brain atrophy (p.Asp67Val) and cerebellar hypoplasia (p.Arg99Leu).
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Factores de Ribosilacion-ADP , Trastornos del Neurodesarrollo , Factores de Ribosilacion-ADP/genética , Factores de Ribosilacion-ADP/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Animales , Encéfalo/metabolismo , Aparato de Golgi/genética , Aparato de Golgi/metabolismo , Mamíferos/metabolismo , Trastornos del Neurodesarrollo/metabolismoRESUMEN
PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.
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Exoma , Malformaciones del Sistema Nervioso , Niño , Humanos , Exoma/genética , Mutación , Malformaciones del Sistema Nervioso/genética , Atrofia/genética , Receptor 1 de Folato/genética , CinesinasRESUMEN
Neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene. This retrospective study aims to evaluate the clinical manifestations and brain magnetic resonance images (MRI) analysis in 60 genetically confirmed NF1 patients. The results of next-generation sequencing (NGS), Sanger sequencing, and MLPA of NF1 gene were evaluated. A total of 54 different variants were identified. Fourteen out of them were novel variants (25.9%). Patients who complied with NIH criteria had most frequently frameshift variants (11/32 patients), and those with only CALMs had missense variants (9/28 patients). Neurofibromatosis type 1 bright objects (NBOs) on T2-weighted MRI were detected in 42 patients (42/56; 75%). These brain lesions were detected mostly in basal ganglia and in cerebellar vermis. NBOs were detected more in the patients who complied with NIH criteria (80.6%) compared to those who were only CALMs (68%). While frameshift variants (33.3%) were the most common type variants in the patients who had NBOs, the most common variants were splicing (35.7%) and missense (35.7%) variants in the patients whose MRIs were normal. Frameshift variants (11/28 patients; 39.3%) were the most common in the patients with more than one brain locus involvement. Therefore, we consider that frameshift variants may be associated with increased incidence of NBOs and involvement of more than one brain locus. In addition, NBOs may occur less frequently in the patients with splicing variants. To our knowledge, this is the first study evaluated the relationship between NF1 gene variants and NBOs. Future studies may help us understand the etiology of NBOs.
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Neurofibromatosis 1 , Encéfalo/diagnóstico por imagen , Genes de Neurofibromatosis 1 , Humanos , Imagen por Resonancia Magnética , Neurofibromatosis 1/diagnóstico por imagen , Neurofibromatosis 1/genética , Neurofibromina 1 , Estudios RetrospectivosRESUMEN
INTRODUCTION: Persistent müllerian duct syndrome (PMDS) is a rare form of 46, XY disorder of sex development characterized by the persistence of the müllerian structures (uterus, fallopian tubes, the upper part of the vagina) in phenotypically and genotypically normal males. This disease occurs as a result of impairment in the synthesis, release or effect of anti-Müllerian hormone (AMH) during the embryonic period. Approximately 85-88% of PMDS cases have been reported to have AMH or AMHRII mutation. CASE: Herein, we report two PMDS cases from unrelated two families who presented with bilateral undescended testes, persistence of müllerian remnants, and low/undetectable serum AMH levels. Molecular genetic analysis revealed two homozygous variants in AMH. The first one is a novel missense variant (c.1315C > T), the latter is a frameshift variant caused by a deletion (c.343_344delCT), which is less frequently reported type in AMH. CONCLUSION: The diagnosis of PMDS should be kept in mind in patients with externally normal males, bilateral cryptorchidism, and signs of müllerian remnants on laparoscopy.
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Hormona Antimülleriana/genética , Trastorno del Desarrollo Sexual 46,XY/genética , Preescolar , Mutación del Sistema de Lectura , Humanos , Lactante , Masculino , Mutación MissenseRESUMEN
We present a Turkish family with two cousins (OC15 and OC15b) affected with syndromic developmental delay, microcephaly, and trigonocephaly but with some phenotypic traits distinct between them. OC15 showed asymmetrical skeletal defects and syndactyly, while OC15b presented with a more severe microcephaly and semilobal holoprosencephaly. All four progenitors were related and OC15 parents were consanguineous. Whole Exome Sequencing (WES) analysis was performed on patient OC15 as a singleton and on the OC15b trio. Selected variants were validated by Sanger sequencing. We did not identify any shared variant that could be associated with the disease. Instead, each patient presented a de novo heterozygous variant in a different gene. OC15 carried a nonsense mutation (p.Arg95*) in PORCN, which is a gene responsible for Goltz-Gorlin syndrome, while OC15b carried an indel mutation in ZIC2 leading to the substitution of three residues by a proline (p.His404_Ser406delinsPro). Autosomal dominant mutations in ZIC2 have been associated with holoprosencephaly 5. Both variants are absent in the general population and are predicted to be pathogenic. These two de novo heterozygous variants identified in the two patients seem to explain the major phenotypic alterations of each particular case, instead of a homozygous variant that would be expected by the underlying consanguinity.
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Aciltransferasas/genética , Consanguinidad , Proteínas de la Membrana/genética , Mutación , Proteínas Nucleares/genética , Factores de Transcripción/genética , Niño , Preescolar , Análisis Mutacional de ADN , Facies , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Linaje , Fenotipo , Radiografía , TurquíaRESUMEN
OBJECTIVE: To evaluate orodental, facial, clinical and molecular characteristics of the patients with Noonan Syndrome (NS). STUDY DESIGN: The orodental, clinical and molecular characteristics of 29 mutation-positive patients with NS were recorded. Orodental examination was performed in 17 patients. All exons and exonintron boundries of PTPN11 and SOS1 genes were analyzed by Sanger sequencing. RESULTS: A total of 29 patients with NS from 27 unrelated families were included in the study. Seventeen patients were examined by a specialist in oral medicine. The most common orodental findings were high-arched palate (n=13), gingivitis (n=6) and severe caries (n=6). Anterior open bite, posterior cross bite, Class II malocclusion, hypodontia, prognathism (maxillary or mandibular), macroglossia and gingival hyperplasia were also detected. Thirteen different mutations were observed in PTPN11 gene and exon 3 was the hotspot region. Hypodontia was detected in two patients who had the same mutation in PTPN11 gene, c.181G>A, p.D61N. CONCLUSION: This study indicated a high prevalance of orodental problems including high-arched palate, severe dental caries and gingivitis in patients with mutation-positive NS. The mutation in PTPN11 gene, c.181G>A, p.D61N, may be associated with hypodontia in patients with NS.
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Caries Dental , Síndrome de Noonan , Mordida Abierta , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Humanos , Mutación , Síndrome de Noonan/genética , Fenotipo , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genéticaRESUMEN
Background and aim: The number of reports on the role of tubulin gene mutations (TUBA1A, TUBB2B, and TUBB3) in etiology of malformations of cortical development has peaked in recent years. We aimed to determine tubulin gene defects on a patient population with simple and complex malformations of cortical development, and investigate the relationship between tubulin gene mutations and disease phenotype. Materials and methods: We evaluated 47 patients with simple or complex malformations of cortical development, as determined by radiological examination, for demographic features, clinical findings and mutations on TUBA1A, TUBB2B, and TUBB3 genes. Results: According to the magnetic resonance imaging findings, 19 patients (40.5%) had simple malformations of cortical development and 28 (59.5%) patients had complex malformations of cortical development. Focal cortical dysplasia was the most common simple malformation, lissencephaly was the most common coexisting cortical malformation, and corpus callosum anomalies were the most common coexisting extracortical neurodevelopmental abnormalities. None of the patients had genetic alterations on TUBA1A, TUBB2B, and TUBB3 genes causing protein dysfunction. On the other hand, the frequencies of some polymorphisms were higher when compared to the literature. Conclusion: It is crucial to identify the etiology in patients with malformations of cortical development in order to provide appropriate genetic counseling and prenatal diagnosis. We consider that multicenter studies with higher patient numbers and also including other malformations of cortical development-related genes are required to determine underlying etiological factors of malformations of cortical development patients.
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Malformaciones del Desarrollo Cortical , Tubulina (Proteína)/genética , Adolescente , Niño , Preescolar , Consanguinidad , Femenino , Humanos , Lactante , Desequilibrio de Ligamiento , Imagen por Resonancia Magnética , Masculino , Malformaciones del Desarrollo Cortical/diagnóstico por imagen , Malformaciones del Desarrollo Cortical/genética , Polimorfismo de Nucleótido Simple/genéticaRESUMEN
Background/aim: CHARGE syndrome is a rare autosomal dominant disease with multiple congenital anomalies and cognitive impairment, which is caused by mutations in the CHD7 gene. This study aimed to disclose the mild end of the phenotypic spectrum of CHARGE syndrome, which has a highly variable expressivity. Materials and methods: Twenty-one patients who had at least one of the major symptoms of CHARGE syndrome (coloboma, choanal atresia, characteristic ear anomalies, semicircular canal hypoplasia, and cranial nerve anomalies) were included in the study. All patients were tested for karyotype analysis and CHD7 gene mutation/deletion. Results: In the study population, 6 different mutations were detected in 5 patients, and 2 different polymorphisms were detected in the CHD7 gene in 3 patients. MLPA analysis of all coding exons of the CHD7 gene revealed no pathogenic deletion/duplication. Conclusion: CHARGE syndrome should be considered as a differential diagnosis to detect the mild end of the spectrum, even if the patient does not fit the criteria.
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Síndrome CHARGE , Síndrome CHARGE/diagnóstico , Síndrome CHARGE/genética , Síndrome CHARGE/patología , Síndrome CHARGE/fisiopatología , Estudios de Casos y Controles , Niño , ADN Helicasas/genética , Proteínas de Unión al ADN/genética , Humanos , Mutación/genética , FenotipoRESUMEN
Ring chromosome 13 is a rare genetic condition with an incidence of 1/58,000 in live births. Major clinical features of patients with ring chromosome 13 include growth and developmental retardation, microcephaly, facial dysmorphism, ambiguous genitalia, anal atresia, eye malformations, retinoblastoma, and hand, foot, and toe abnormalities. The severity of the phenotype depends on the amount of genetic material lost during ring chromosome formation. Here, we report 2 cases with ring chromosome 13 at either end of the phenotypic spectrum.
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Anomalías Múltiples/genética , Agenesia del Cuerpo Calloso/genética , Trastornos de los Cromosomas/genética , Cardiopatías Congénitas/genética , Microcefalia/genética , Astigmatismo/genética , Trastornos de los Cromosomas/patología , Cromosomas Humanos Par 13/genética , Cromosomas Humanos Par 13/ultraestructura , Hibridación Genómica Comparativa , Resultado Fatal , Femenino , Retardo del Crecimiento Fetal/genética , Pérdida Auditiva Bilateral/genética , Pérdida Auditiva Sensorineural/genética , Humanos , Lactante , Recién Nacido , Trastornos del Desarrollo del Lenguaje/genética , Fenotipo , Polihidramnios/etiología , Embarazo , Cromosomas en Anillo , Análisis de Matrices TisularesRESUMEN
OBJECTIVE: Brucellosis is an important infectious disease, especially in developing countries, and may involve any organ, including the cardiovascular system. This study aimed to assess cardiac and endothelial functions in brucellosis patients. METHODS: Seventy-three patients with brucellosis and seventy-five healthy volunteers from Turkey were enrolled between 2011 and 2013 in this cross-sectional study. Diagnosis was established by the Rose-Bengal test, positive Brucella standart tube agglutination test, and Coombs STA and/or isolation Brucella species from blood. Cases were divided into three groups: Group I; acute brucellosis, Group II; subacute brucellosis, and Group III; chronic brucellosis. Healthy individuals comprised Group IV. All patients underwent transthoracic echocardiography and brachial artery flow-mediated dilatation (FMD) test. RESULTS: Groups I to IV comprised 35, 18, and 20 patients, and 75 controls respectively. The most frequent symptoms were arthralgia (82%), fever (92%), and fatigue (97%). Echocardiography revealed no difference among the 4 groups regarding left ventricular systolic and diastolic functions and valvular functions. Brachial artery diameter after hyperemia was significantly different among the groups (p=0.002). Post hoc test showed Group III to have significantly lower brachial artery diameter after hyperemia compared to other groups (p=0.02, p=0.004 and p=0.001, respectively). FMD was also significantly lower in Group III compared to Groups I, II and IV (p<0.001 for each). CONCLUSION: Brucellosis impairs endothelial functions in chronic symptomatic patients without overt cardiac involvement.
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Brucelosis/fisiopatología , Endotelio Vascular/fisiopatología , Cardiopatías/microbiología , Adulto , Estudios Transversales , Ecocardiografía , Femenino , Cardiopatías/fisiopatología , Pruebas de Función Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
OBJECTIVES: Nuclear receptor subfamily 5 group A member 1 (NR5A1) is a transcription factor critical for the development of various organs. Pathogenic variants in NR5A1 are associated with a spectrum of disorders of sex development (DSD). CASE PRESENTATION: A 15-month-old baby, raised as a girl, was referred for genital swelling and ambiguous genitalia. Born to healthy consanguineous parents, the baby had a phallus, perineal hypospadias, labial fusion, and a hypoplastic scrotum. Hormonal evaluation showed normal levels, and ultrasonography revealed small gonads and absence of Müllerian derivatives. Post-human chorionic gonadotropin (hCG) testing indicated an adequate testosterone response. The karyotype was 46,XY, and in it was found a homozygous NR5A1 variant (c.307 C>T, p.Arg103Trp) in a custom 46 XY DSD gene panel. Notably, the patient exhibited complete sex reversal, hyposplenia, and no adrenal insufficiency. CONCLUSIONS: Previously, NR5A1 pathogenic variants were considered to be dominantly inherited, and homozygous cases were thought to be associated with adrenal insufficiency. Despite the homozygous pathogenic variant, our patient showed hyposplenism with normal adrenal function; this highlights the complexity of NR5A1 genotype-phenotype correlations. These patients should be monitored for adrenal insufficiency and DSD as well as splenic function.
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Trastorno del Desarrollo Sexual 46,XY , Homocigoto , Factor Esteroidogénico 1 , Humanos , Factor Esteroidogénico 1/genética , Trastorno del Desarrollo Sexual 46,XY/genética , Femenino , Masculino , Lactante , Mutación , PronósticoRESUMEN
Marshall-Smith syndrome (MSS) and Malan syndrome (MS) are both allelic disorders caused by mutations in the NFIX gene. MS is characterized by overgrowth, intellectual disability, distinctive facial features, and accelerated skeletal maturation. On the other hand, clinical features of MSS consist of advanced bone age, dysmorphic features, intellectual disability, and failure to thrive at birth. In this study, we presented the clinical and molecular findings of two different patients with MS and MSS as a rare cause of intellectual disability and reported two novel variants in the NFIX gene. NFIX gene sequencing revealed a novel heterozygous c.1287delC (p.G430Vfs*34) mutation in patient 1 whose clinical diagnosis was compatible with Marshall-Smith syndrome, and in the second patient, physical features consistent with Malan syndrome, was detected a heterozygous one nucleotide duplication, c.303dupC (pCys102LeufsTer17).
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Discapacidad Intelectual , Recién Nacido , Humanos , Discapacidad Intelectual/complicaciones , Discapacidad Intelectual/genética , Factores de Transcripción NFI/genética , Fenotipo , Mutación/genéticaRESUMEN
Objective: Congenital hypopituitarism (CH) is a rare disease characterized by one or more hormone deficiencies of the pituitary gland. To date, many genes have been associated with CH. In this study, we identified the allelic variant spectrum of 11 causative genes in Turkish patients with CH. Materials and methods: This study included 47 patients [21 girls (44.6%) and 26 boys (55.4%)] from 45 families. To identify the genetic etiology, we screened 11 candidate genes associated with CH using next-generation sequencing. To confirm and detect the status of the specific familial variant in relatives, Sanger sequencing was also performed. Results: We identified 12 possible pathogenic variants in GHRHR, GH1, GLI2, PROP-1, POU1F1, and LHX4 in 11 patients (23.4%), of which six were novel variants: two in GHRHR, two in POU1F1, one in GLI2, and one in LHX4. In all patients, these variants were most frequently found in GLI2, followed by PROP-1 and GHRHR. Conclusion: Genetic causes were determined in only 23.4% of all patients with CH and 63% of molecularly diagnosed patients (7/11) from consanguineous families. Despite advances in genetics, we were unable to identify the genetic etiology of most patients with CH, suggesting the effect of unknown genes or environmental factors. More genetic studies are necessary to understand the etiology of CH.
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Hipopituitarismo , Femenino , Humanos , Masculino , Alelos , Hipopituitarismo/diagnóstico , Hipopituitarismo/genética , Mutación , Proteínas Nucleares/genética , Factor de Transcripción Pit-1/genética , Factores de Transcripción/genética , Proteína Gli2 con Dedos de Zinc/genéticaRESUMEN
Coffin-Lowry syndrome (CLS) is a rare X-linked disorder that, usually affects males, presenting with intellectual disability, short stature, growth retardation, short hands, hyperextensible fingers and progressive kyphoscoliosis. Due to skewed X chromosome inactivation, the clinical presentations of the affected females vary greatly and clinical manifestations could range from mild intellectual disability to typical features of CLS in males. Here, we reported two different novel RPS6KA3 gene mutations in two unrelated CLS patients and also described concomitant compulsive eyebrow-pulling behavior in one of these cases for the first time in the literature.
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Síndrome de Coffin-Lowry , Discapacidad Intelectual , Síndrome de Coffin-Lowry/genética , Conducta Compulsiva , Cejas , Femenino , Humanos , Discapacidad Intelectual/genética , Mutación/genéticaRESUMEN
OBJECTIVES: Non-syndromic monogenic obesity is a rare cause of early-onset severe obesity in the childhood period. The aim of this study was to screen four obesity related genes (LEP, LEPR, MC4R and POMC) in children and adolescents who had severe, non-syndromic early onset obesity. METHODS: Next-generation sequencing of all exons in LEP, LEPR, MC4R and POMC was performed in 154 children and adolescents with early onset severe obesity obesity. RESULTS: Fifteen different variants in nineteen patients were identified with a variant detection rate of 12.3%. While six different heterozygous variants were observed in MC4R gene (10/154 patients; 6.5%), five different variants in POMC gene (four of them were heterozygous and one of them was homozygous) (6/154 patients; 3.9%) and four different homozygous variants in LEPR gene (3/154 patients; 1.9%) were described. However, no variants were detected in the LEP gene. The most common pathogenic variant was c.496G>A in MC4R gene, which was detected in four unrelated patients. Six novel variants (6/15 variants; 40%) were described in seven patients. Four of them including c.233C>A and c.752T>C in MC4R gene and c.761dup and c.1221dup in LEPR gene were evaluated as pathogenic or likely pathogenic. CONCLUSIONS: In conclusion, MC4R variants are the most common genetic cause of monogenic early-onset obesity, consistent with the literature. The c.496G>A variant in MC4R gene is highly prevalent in early-onset obese patients.
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Obesidad Mórbida , Receptor de Melanocortina Tipo 4 , Adolescente , Niño , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mutación , Obesidad/genética , Obesidad Mórbida/genética , Proopiomelanocortina/genética , Receptor de Melanocortina Tipo 4/genética , Receptores de Leptina/genéticaRESUMEN
Objectives: Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive diseases characterized by salt wasting or virilization. 21 hydroxylase deficiency (21-OHD) accounts for 90-95% of all cases of CAH and caused by the genetic defects of CYP21A2. Other forms include 3-ß-hydroxysteroid dehydrogenase deficiency, 11-ß-hydroxylase deficiency (11ß-OHD) (%5-8), 17-α-hydroxylase deficiency (17α-OHD), and steroidogenic acute regulatory protein (STAR) defects (congenital lipoid adrenal hyperplasia) with mutations in HSD3B2, CYP11B1, CYP17A1, and STAR, respectively. Objectives: Herein, we aimed to present the clinical and genetic features of 64 patients with various types of CAH. Methods: Sixty-four patients with CAH, monitored in the Izmir Dr. Behcet Uz Children Hospital Division of Pediatric Endocrinology, were retrospectively analyzed for the clinical, laboratory, and genetic data. Results: Fifty-six patients (87.5%) had 21-OHD and four patients (6.3%) had 17α-OHD, three patients (4.7%) had 11ß-OHD, and one patient (1.5%) had STAR defect. The most common presenting features in 21-OHD were ambiguous genitalia. Patients with 21-OHD were diagnosed earlier than the rare groups. Disease-causing variants of CYP21A2 were identified in 46 patients. The most common mutations were IVS2, Q318X, I172N, and large deletions. Three patients with 11ß-OHD were presented with enlargement of penis and early pubic hair at the median presenting age of 26 months. 17α-OHD deficiency was detected in 4 cases. Genetic analysis revealed two different homozygous CYP17A1 variants. The patient with STAR defect was presented with dehydration and cholestasis in 44 days of the life. Genetic analysis of patient with STAR deficiency revealed a novel homozygous variant. Conclusion: The current study reported a genotype-phenotype correlation consistent with literature data in CAH cases with 21-OHD. This study also reported novel homozygous variants in STAR and CYP17A1 genes that lead to rare types of CAH.
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Dysosteosclerosis (DOS) is a rare sclerosing bone dysplasia characterized by unique osteosclerosis of the long tubular bones and platyspondyly. DOS is inherited in an autosomal recessive manner and is genetically and clinically heterogeneous. To date, four individuals with DOS who have five different TNFRSF11A mutations have been reported. Based on their data, it is hypothesized that mutations producing aberrant mutant RANK proteins (missense or truncated or elongated) cause DOS, while null mutations lead to osteopetrosis, autosomal recessive 7 (OPTB7). Herein, we present the fifth case of TNFRSF11A-associated DOS with a novel homozygous frame-shift mutation (c.19_31del; p.[Arg7CysfsTer172]). The mutation is predicted to cause nonsense mutation-mediated mRNA decay (NMD) in all RANK isoform transcripts, resulting in totally null allele. Our findings suggest genotype-phenotype relationship in TNFRSF11A-associated OPTB7 and DOS remains unclear, and that the deficiency of TNFRSF11A functions might cause DOS, rather than osteopetrosis. More data are necessary to understand the phenotypic spectrum caused by TNFRSF11A mutations.
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Autosomal recessive osteopetrosis is also known as infantile malignant osteopetrosis (IMO). The clinical course is often serious and if left untreated, it is fatal in the 1st year of life. Diagnosis is challenging and often delayed or misdiagnosed. Herein, we present an infant girl who was diagnosed with IMO during evaluations for her hypotonicity and thrombocytopenia. A novel mutation of the chloride voltage-gated channel 7 (CLCN7) gene was also reported. A 10-day-old female patient was referred to our hospital for evaluation of hypotonicity. Her physical examination was normal, other than hypotonicity. Laboratory analysis revealed thrombocytopenia and hypocalcemia. In the progress, while she was followed in outpatient clinic, hepatosplenomegaly was detected at the age of 3 months. IMO was suspected with the findings of hepatosplenomegaly, cytopenia, hypocalcemia, difficulty of obtaining bone marrow, peripheral smear findings, and hearing loss. The X-ray of the bones was consistent with IMO. A novel pathogenic homozygous c.1504>T (p.Arg502Trp) mutation in CLCN7 gene was revealed. IMO is a rare disorder and it is important to differentiate this entity for better clinical outcome. The presence of neurological and hematological findings, organomegaly, hearing loss, and vision disorders must attract attention to IMO.
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Craniofrontonasal syndrome (CFNS) is a rare X-linked genetic disorder which is characterized by coronal synostosis, widely spaced eyes, a central nasal groove, and various skeletal anomalies. Mutations in the EFNB1 gene in Xq13.1 are responsible for familial and sporadic cases. In the present study, we aimed to evaluate the clinical characteristics and molecular results of 4 patients with CFNS. Genomic DNA was extracted from the peripheral blood lymphocytes of all patients and their parents, and Sanger sequencing of the EFNB1 gene was performed. A novel EFNB1 gene mutation (c.65delG; p.Cys22SerfsTer24) was detected in a newborn who had only dysmorphic facial features and bicornuate uterus. The other 3 patients (2 familial cases and 1 sporadic case) shared the same mutation (c.196C>T; p.R66X). However, the clinical features of these patients were highly variable. Additionally, central (meso-axial) polydactyly and deep palmar creases were detected, which have not been previously reported. CFNS has a wide clinical spectrum, but there is no clear genotype-phenotype correlation. However, central (meso-axial) polydactyly and deep palmar creases may be part of the clinical spectrum seen in CFNS. In addition, our findings expand the mutational spectrum in patients with CFNS.
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Myhre syndrome is a rare autosomal dominant multisystemic disorder. Typical features of this disorder include distinctive facial appearance, deafness, intellectual disability, cardiovascular abnormalities, short stature, brachydactyly, and skeletal anomalies. Gain-of-function mutations in the SMAD4 gene are responsible for this syndrome. Herein, we present a 9.6-year-old Turkish girl with molecularly confirmed Myhre syndrome who had novel findings including bilateral Axenfield Rieger anomaly with secondary glaucoma and bilateral enlarged vestibular aqueducts.