ABCD syndrome, an uncommon cause of hypercalcemia in pediatrics. / Síndrome ABCD, una causa infrecuente de hipercalcemia en pediatría.

ABCD syndrome (ABnormal Calcium, Calcinosis, and Creatinine in Down syndrome) is characterized by an association of hypercalcemia, hypercalciuria, nephrocalcinosis, and impaired kidney function in patients with Down syndrome. Only 7 cases have been published worldwide, although it is believed to be underdiagnosed. This report describes 2 new patients with ABCD syndrome and compares them with the cases reported to date. Although it is a rare cause of pediatric hypercalcemia, it should be considered in children with Down syndrome once other more common etiologies have been ruled out. Once this diagnosis is confirmed, the recommended treatment is to reduce dietary calcium intake and work with an interdisciplinary team to maintain an adequate calorie and protein intake.

El síndrome ABCD (por sus siglas en inglés, ABnormal Calcium, Calcinosis and Creatinine in Down syndrome) se caracteriza por la asociación de hipercalcemia, hipercalciuria, nefrocalcinosis y alteración de la función renal en pacientes con síndrome de Down. Existen solo 7 casos previamente publicados en el mundo, aunque se cree que está subdiagnosticado. En este reporte, presentamos 2 nuevos pacientes con este síndrome y realizamos una comparación con los casos informados hasta el momento. Si bien es una causa rara de hipercalcemia pediátrica, debe considerarse en niños con síndrome de Down una vez descartadas otras etiologías más frecuentes. Al confirmarse este diagnóstico, el tratamiento recomendado es la reducción de calcio en la dieta, trabajando de manera interdisciplinaria para mantener un aporte calórico proteico adecuado.

Exome Sequencing has a high diagnostic rate in sporadic congenital hypopituitarism and reveals novel candidate genes.

CONTEXT: The pituitary gland is key for childhood growth, puberty, and metabolism. Pituitary dysfunction is associated with a spectrum of phenotypes, from mild to severe. Congenital Hypopituitarism (CH) is the most commonly reported pediatric endocrine dysfunction with an incidence of 1:4000, yet low rates of genetic diagnosis have been reported. OBJECTIVE: We aimed to unveil the genetic etiology of CH in a large cohort of patients from Argentina. METHODS: We performed whole exome sequencing of 137 unrelated cases of CH, the largest cohort examined with this method to date. RESULTS: Of the 137 cases, 19.1% and 16% carried pathogenic or likely pathogenic variants in known and new genes, respectively, while 28.2% carried variants of uncertain significance. This high yield was achieved through the integration of broad gene panels (genes described in animal models and/or other disorders), an unbiased candidate gene screen with a new bioinformatics pipeline (including genes high loss of function intolerance), and analysis of copy number variants. Three novel findings emerged. First, the most prevalent affected gene encodes the cell adhesion factor ROBO1. Affected children had a spectrum of phenotypes, consistent with a role beyond pituitary stalk interruption syndrome. Second, we found that CHD7 mutations also produce a phenotypic spectrum, not always associated with full CHARGE syndrome. Third, we add new evidence of pathogenicity in the genes PIBF1 and TBC1D32, and report 13 novel candidate genes associated with CH (e.g. PTPN6, ARID5B). CONCLUSION: Overall, these results provide an unprecedented insight into the diverse genetic etiology of hypopituitarism.

Surgical treatment of secondary hyperparathyroidism in children with chronic kidney disease. Experience in 19 patients.

OBJECTIVES: Secondary hyperparathyroidism (sHPT) is an important contributor to bone disease and cardiovascular calcifications in children with chronic kidney disease (CKD). When conservative measures are ineffective, parathyroidectomy is indicated. The aim of our study was to evaluate the efficacy and safety of subtotal parathyroidectomy (sPTX) in pediatric and adolescent patients, and to provide a rationale for considering this aggressive treatment in CKD patients with uncontrolled sHPT. METHODS: We retrospectively analyzed the medical records of 19 pediatric CKD patients on dialysis with refractory sHPT who underwent sPTX at our institution between 2010 and 2020. All patients had clinical, radiological, and biochemical signs of renal osteodystrophy. RESULTS: One year after sPTX, parathyroid hormone (PTH) levels (median and interquartile range (IQR)) dropped from 2073 (1339-2484) to 164 (93-252) pg/mL (p=0.0001), alkaline phosphatase (ALP) levels from 1166 (764-2373) to 410 (126-421) IU/L (p=0.002), and the mean (±SDS) calcium-phosphate (Ca*P) product from 51±11 to 41±13 mg2/dL2 (p=0.07). Postoperatively, all patients presented with severe hungry bone syndrome (HBS) and required intravenous and oral calcium and calcitriol supplementation. None of them had other postoperative complication. Histological findings had a good correlation with preoperative parathyroid ultrasound imaging (n: 15) in 100 % and with technetium-99m (99mTc) sestamibi scintigraphy (n: 15) in 86.6 %. Clinical and radiological signs of bone disease improved in all patients. CONCLUSIONS: Pediatric sPTX is effective and safe to control sHPT and calcium-phosphate metabolism in children with CKD on dialysis and may mitigate irreversible bone deformities and progression of cardiovascular disease.

A Surgical and Clinical Approach to Persistent Müllerian Duct Syndrome: Laparoscopic, Histological, and Molecular Findings.

BACKGROUND: Persistent müllerian duct syndrome (PMDS) is characterized by the persistence of müllerian duct derivatives in otherwise normally virilized 46,XY males. Biallelic mutations of the anti-müllerian hormone (AMH) and AMH receptor type 2 (AMHR2) genes lead to PMDS type 1 and 2, respectively. AIM: The aims of the study were to report the clinical, hormonal, and genetic findings in a patient with PMDS and discuss surgical strategies to achieve successful orchidopexy. RESULTS: A 4-year-old boy was evaluated after the incidental finding of müllerian derivates during laparoscopy for nonpalpable gonads. Karyotype was 46,XY and laboratory tests revealed normal serum gonadotropin and androgen levels but undetectable serum AMH levels. PMDS was suspected. Molecular analysis revealed a novel variant c.902_929del in exon 5 and a previously reported mutation (c.367C>T) in exon 1 of the AMH gene. Successful orchidopexy was performed in two sequential surgeries in which the müllerian duct structure was preserved and divided to protect the vascular supply to the gonads. Histological evaluation of the testicular biopsy showed mild signs of dysgenesis. Doppler ultrasound showed blood flow in both testes positioned in the scrotum 1.5 years after surgery. CONCLUSION: PMDS is a rare entity that requires a high index of suspicion (from surgeons) when evaluating a patient with bilateral cryptorchidism. Surgical treatment is challenging and long-term follow-up is essential. Histological evaluation of the testis deserves further investigation.

Gonadal tumor development in 46,XX disorders of gonadal development.

Background: Differences/disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Objective: The aim of this study is to report the histological characteristics and immunoexpression patterns of gonadal parenchyma in patients with 46,XX testicular and ovotesticular DSD, with a focus on the detection of germ cell malignancies. Design: Inclusion criteria were SRY-negative 46,XX testicular and ovotesticular DSD with available samples from gonadal biopsy or gonadectomy for the review of histological findings. Gonadal histology was assessed on hematoxylin and eosin-stained sections and immunohistochemical analysis. Histopathological criteria from the last World Health Organization classification of urogenital tumors were used to identify undifferentiated gonadal tissue, gonadoblastoma, and dysgerminoma. Results: Median age at first histological evaluation of gonadal samples was 1.46 years (range: 0.16-16 years). Totally 15 patients were classified as ovotesticular and only 1 as testicular DSD. Most individuals had bilateral ovotestes (12/15). No histological alterations were found in the ovarian parenchyma, while signs of dysgenesis were seen in all cases of testicular parenchyma. In 4/15 ovotesticular DSD, a prepubertal biopsy failed to identify ovarian parenchyma. We detected early prepubertal preinvasive and invasive malignancies in this cohort (five patients had undifferentiated gonadal tissue, five gonadoblastoma, and one dysgerminoma). Conclusion: 46,XX disorders of gonadal development are historically considered at a low risk for germ cell cancer, and the need for assessment of gonadal histology has been questioned. The finding of early germ cell malignancies in our cohort brings awareness and needs further research.

Pediatric adrenocortical tumors cohort characteristics and long-term follow-up at a single Argentinian tertiary center.

Pediatric adrenocortical tumors are rare and heterogeneous endocrine malignancies. OBJECTIVES: To report clinical, biochemical, and histological features, staging, and therapeutic interventions in a cohort of 28 patients treated at a single tertiary center. METHODS: A retrospective review of medical records of children with PACT (diagnosed before <18 years of age) followed between 1987-2018 at Hospital de Pediatría Garrahan, Buenos Aires, Argentina. RESULTS: Mean age at diagnosis was 4.6 years (range, 0.3-17.3 years) and median follow-up was 4.17 years (range, 0-12 years). Female to male ratio was 2.5:1. Signs and symptoms that prompted medical intervention were hormonal overproduction (57%), abdominal complaints (36%), and hypertensive encephalopathy (7%). In patients with clinically virilizing tumors (n=16) mean height standard deviation score (SDS) and bone age advance were significantly higher while body mass index (BMI) SDS was significantly lower than in those with clinical Cushing's (n=10) (p<0.05). Serum dehydroepiandrosterone sulfate (DHEAS) levels were significantly higher in stage IV than in stage I (p=0.03). Total adrenalectomy was performed in 26 patients. Eight patients (stage III-IV) received adjuvant chemotherapy. Five-year overall and disease-free survival were 100% for ST I-II, and 51% (95% CI 21-82) and 33% (95% CI 1.2-65) for ST III-IV, respectively (p=0.002). No statistical difference was found when comparing 2-year parameters with and without adjuvant chemotherapy. CONCLUSIONS: Height SDS and BMI SDS seem to mirror hormonal secretion in pediatric adrenocortical tumors. Higher DHEAS levels were found in patients with more advanced disease. Further large-scale studies are needed to validate a possible role for DHEAS as a biochemical marker of tumor stage and to draw robust conclusions on the use of adjuvant chemotherapy.

Comprehensive Identification of Pathogenic Gene Variants in Patients With Neuroendocrine Disorders.

PURPOSE: Congenital hypopituitarism (CH) can present in isolation or with other birth defects. Mutations in multiple genes can cause CH, and the use of a genetic screening panel could establish the prevalence of mutations in known and candidate genes for this disorder. It could also increase the proportion of patients that receive a genetic diagnosis. METHODS: We conducted target panel genetic screening using single-molecule molecular inversion probes sequencing to assess the frequency of mutations in known hypopituitarism genes and new candidates in Argentina. We captured genomic deoxyribonucleic acid from 170 pediatric patients with CH, either alone or with other abnormalities. We performed promoter activation assays to test the functional effects of patient variants in LHX3 and LHX4. RESULTS: We found variants classified as pathogenic, likely pathogenic, or with uncertain significance in 15.3% of cases. These variants were identified in known CH causative genes (LHX3, LHX4, GLI2, OTX2, HESX1), in less frequently reported genes (FOXA2, BMP4, FGFR1, PROKR2, PNPLA6) and in new candidate genes (BMP2, HMGA2, HNF1A, NKX2-1). CONCLUSION: In this work, we report the prevalence of mutations in known CH genes in Argentina and provide evidence for new candidate genes. We show that CH is a genetically heterogeneous disease with high phenotypic variation and incomplete penetrance, and our results support the need for further gene discovery for CH. Identifying population-specific pathogenic variants will improve the capacity of genetic data to predict eventual clinical outcomes.

Respuesta al lenvatinib en una paciente pediátrica con insuficiencia respiratoria secundaria a carcinoma papilar de tiroides / Response to lenvatinib in a pediatric patient with respiratory failure associated with papillary thyroid carcinoma

El cáncer papilar de tiroides es el tumor tiroideo más común en la infancia. En estadios avanzados, puede presentarse con cuadro de insuficiencia respiratoria. El tratamiento de elección es la tiroidectomía total y iodo radiactivo. En tumores irresecables, se debería considerar terapia con inhibidores multicinasa.Niña de 10 años de edad derivada por insuficiencia respiratoria progresiva. Se realizó el diagnóstico de cáncer papilar de tiroides con metástasis pulmonares. Por presentar un tumor irresecable no pasible de cirugía, se indicó el uso compasivo de lenvatinib, que mostró una rápida y favorable respuesta clínica con resolución de la insuficiencia respiratoria al noveno día del tratamiento.El diagnóstico temprano de cáncer papilar de tiroides previene la grave morbilidad respiratoria ocasionada por diagnósticos tardíos. Podría considerarse el uso de lenvatinib como alternativa previa a las terapias de primera línea (cirugía e iodo radiactivo) en casos de enfermedad con gran compromiso local y a distancia.

Papillary thyroid cancer is the most common thyroid tumor in childhood. In advanced stages, it can present with respiratory failure. The treatment of choice is total thyroidectomy and radioactive iodine. In cases of unresectable tumors, therapy with multikinase inhibitors should be considered. A 10-year-old girl was referred for progressive respiratory failure. A diagnosis of papillary thyroid cancer with pulmonary metastases was made. Due to the presence of an unresectable tumor not subject to surgery, the compassionate use of lenvatinib was indicated, showing a rapid and favorable clinical response with resolution of respiratory failure on the ninth day.Early diagnosis of papillary thyroid cancer prevents severe respiratory morbidity caused by late diagnoses. The use of lenvatinib should be considered as a previous step towards first-line therapies (surgery and radioactive iodine) in cases with great local and distant involvement.

[Response to lenvatinib in a pediatric patient with respiratory failure associated with papillary thyroid carcinoma]. / Respuesta al lenvatinib en una paciente pediátrica con insuficiencia respiratoria secundaria a carcinoma papilar de tiroides.

Papillary thyroid cancer is the most common thyroid tumor in childhood. In advanced stages, it can present with respiratory failure. The treatment of choice is total thyroidectomy and radioactive iodine. In cases of unresectable tumors, therapy with multikinase inhibitors should be considered. A 10-year-old girl was referred for progressive respiratory failure. A diagnosis of papillary thyroid cancer with pulmonary metastases was made. Due to the presence of an unresectable tumor not subject to surgery, the compassionate use of lenvatinib was indicated, showing a rapid and favorable clinical response with resolution of respiratory failure on the ninth day. Early diagnosis of papillary thyroid cancer prevents severe respiratory morbidity caused by late diagnoses. The use of lenvatinib should be considered as a previous step towards first-line therapies (surgery and radioactive iodine) in cases with great local and distant involvement.

El cáncer papilar de tiroides es el tumor tiroideo más común en la infancia. En estadios avanzados, puede presentarse con cuadro de insuficiencia respiratoria. El tratamiento de elección es la tiroidectomía total y iodo radiactivo. En tumores irresecables, se debería considerar terapia con inhibidores multicinasa. Niña de 10 años de edad derivada por insuficiencia respiratoria progresiva. Se realizó el diagnóstico de cáncer papilar de tiroides con metástasis pulmonares. Por presentar un tumor irresecable no pasible de cirugía, se indicó el uso compasivo de lenvatinib, que mostró una rápida y favorable respuesta clínica con resolución de la insuficiencia respiratoria al noveno día del tratamiento. El diagnóstico temprano de cáncer papilar de tiroides previene la grave morbilidad respiratoria ocasionada por diagnósticos tardíos. Podría considerarse el uso de lenvatinib como alternativa previa a las terapias de primera línea (cirugía e iodo radiactivo) en casos de enfermedad con gran compromiso local y a distancia.

Presentación atípica de un prolactinoma gigante en un adolescente de 15 años / Atypical presentation of a giant prolactinoma in a 15-year-old boy

El prolactinoma gigante es un adenoma pituitario poco frecuente caracterizado por su gran invasión local. Se reporta el caso de un varón de 15 años de edad con dolor retroocular izquierdo y exoftalmos ipsilateral de 4 meses de evolución secundario a un tumor en la base del cráneo que invadía la órbita. Los estudios hormonales revelaron prolactina sérica de 6913,7 ng/ml (valor normal < 20), que confirmó el diagnóstico de prolactinoma gigante. El paciente inició un tratamiento con el agonista dopaminérgico cabergolina en dosis crecientes. Luego de 7 meses de seguimiento, la prolactina había descendido a 349,8 ng/ml y el volumen del tumor se redujo un 70%, sin efectos adversos al tratamiento. El paciente se encontraba asintomático y había reiniciado la pubertad. La rápida remisión de los síntomas sin necesidad de tratamientos invasores subraya la importancia de considerar el diagnóstico de prolactinoma entre los posibles diagnósticos diferenciales de tumor de la base del cráneo.

Giant prolactinomas are rare pituitary adenomas characterized by their great local invasion. In this paper, we report a 15-year-old male with left retro-ocular pain and ipsilateral exophthalmos of 4 months of evolution, secondary to a tumour in the base of the skull that invaded the orbit. Hormonal studies revealed serum prolactin of 6913,7 ng/ml (normal value < 20), confirming the diagnosis of giant prolactinoma. The patient started treatment with the dopaminergic agonist cabergoline in increasing doses. After 7 months of follow-up the prolactin had decreased to 349.8 ng/ml and the tumor volume was reduced by 70%, without presenting adverse effects to the treatment. The patient was asymptomatic and had restarted puberty. The rapid remission of symptoms without the need for invasive treatments underlines the importance of considering the diagnosis of prolactinoma among the possible differential diagnoses of tumor of the skull base.

[Atypical presentation of a giant prolactinoma in a 15-year-old boy]. / Presentación atípica de un prolactinoma gigante en un adolescente de 15 años.

Giant prolactinomas are rare pituitary adenomas characterized by their great local invasion. In this paper, we report a 15-year-old male with left retro-ocular pain and ipsilateral exophthalmos of 4 months of evolution, secondary to a tumour in the base of the skull that invaded the orbit. Hormonal studies revealed serum prolactin of 6913,7 ng/ml (normal value < 20), confirming the diagnosis of giant prolactinoma. The patient started treatment with the dopaminergic agonist cabergoline in increasing doses. After 7 months of follow-up the prolactin had decreased to 349.8 ng/ml and the tumor volume was reduced by 70%, without presenting adverse effects to the treatment. The patient was asymptomatic and had restarted puberty. The rapid remission of symptoms without the need for invasive treatments underlines the importance of considering the diagnosis of prolactinoma among the possible differential diagnoses of tumor of the skull base.

El prolactinoma gigante es un adenoma pituitario poco frecuente caracterizado por su gran invasión local. Se reporta el caso de un varón de 15 años de edad con dolor retroocular izquierdo y exoftalmos ipsilateral de 4 meses de evolución secundario a un tumor en la base del cráneo que invadía la órbita. Los estudios hormonales revelaron prolactina sérica de 6913,7 ng/ml (valor normal < 20), que confirmó el diagnóstico de prolactinoma gigante. El paciente inició un tratamiento con el agonista dopaminérgico cabergolina en dosis crecientes. Luego de 7 meses de seguimiento, la prolactina había descendido a 349,8 ng/ml y el volumen del tumor se redujo un 70%, sin efectos adversos al tratamiento. El paciente se encontraba asintomático y había reiniciado la pubertad. La rápida remisión de los síntomas sin necesidad de tratamientos invasores subraya la importancia de considerar el diagnóstico de prolactinoma entre los posibles diagnósticos diferenciales de tumor de la base del cráneo.

Series de Pediatría Garrahan. El niño con cáncer / Garrahan Pediatrics Series. The child with cancer

La sobrevida de los niños con enfermedades oncológicas ha aumentado de manera considerable en las últimas décadas y este logro se alcanzó, entre otros factores, gracias a la detección temprana de la patología, los avances en los métodos diagnósticos, la administración de terapéuticas específicas adaptadas al riesgo y la adecuada implementación de medidas de soporte. Sin embargo, el cuidado de estos pacientes sigue representando un difícil desafío y requiere la conformación de equipos en los que el pediatra cumple un rol fundamental en la atención conjunta con el oncólogo y en la coordinación de la intervención de los demás especialistas. Este nuevo volumen aborda esta interesante temática y entre sus características destacadas se encuentran: El estudio de importantes temas, como la prevención del cáncer en pediatría en el mundo y en la Argentina, y la necesidad de construir programas de integración, educación e investigación en el cáncer pediátrico; el niño con una masa abdominal, con sus estrategias diagnósticas y las eventuales urgencias metabólicas, infectológicas y nutricionales durante el período de inducción, y cómo anticiparlas y prevenirlas; las situaciones clínicas de riesgo, como la compresión medular, el síndrome de vena cava superior y las complicaciones asociadas con la utilización de irinotecán; los aspectos ginecológicos en las niñas con cáncer, como las conductas frente al riesgo de sangrado menstrual durante el período de inducción, la actividad sexual y el embarazo durante el tratamiento, y la preservación de la fertilidad; y la leucemia linfoblástica aguda en etapa de reinducción, período especialmente significativo por la elevada morbilidad y las dificultades en el soporte clínico que requieren estos pacientes. La inclusión en todos los capítulos de casos clínicos ejemplificadores con su evolución y desenlace, textos destacados con los conceptos más importantes y puntos clave para recordar. Una obra sólida y práctica, que transmite la experiencia de los profesionales de una institución del prestigio internacional del Hospital de Pediatría Prof. Dr. Juan P. Garrahan, dedicada a todos los pediatras dondequiera que trabajen al servicio de los niños.

Two novel heterozygous missense variations within the GLI2 gene in two unrelated Argentine patients.

Several heterozygous GLI2 gene mutations have been reported in patients with isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD) with or without other malformations. The primary aim of this study was to analyze the presence of GLI2 gene alterations in a cohort of patients with IGHD or MPHD and ectopic/absent posterior pituitary. The coding sequence and flanking intronic regions of GLI2 gene were amplified and directly sequenced from gDNA of 18 affected subjects and relatives. In silico tools were applied to identify the functional impact of newly found variants (Polyphen2, SIFT, Mutation Taster). We identified two novel heterozygous missense variations in two unrelated patients, p.Arg231Gln and p.Arg226Leu, located in the repressor domain of the protein. Both variations affect highly conserved amino acids of the Gli2 protein and were not found in the available databases. In silico tools suggest that these variations might be disease causing. Our study suggests that the GLI2 gene may be one of the candidate genes to analyze when an association of pituitary hormone deficiency and developmental defects in posterior pituitary gland. The highly variable phenotype found suggests the presence of additional unknown factors that could contribute to the phenotype observed in these patients.

Two novel heterozygous missense variations within the GLI2 gene in two unrelated argentine patients / Two novel heterozygous missense variations within the GLI2 gene in two unrelated Argentine patients

Several heterozygous GLI2 gene mutations have been reported in patients with isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD) with or without other malformations. The primary aim of this study was to analyze the presence of GLI2 gene alterations in a cohort of patients with IGHD or MPHD and ectopic/absent posterior pituitary. The coding sequence and flanking intronic regions of GLI2 gene were amplified and directly sequenced from gDNA of 18 affected subjects and relatives. In silico tools were applied to identify the functional impact of newly found variants (Polyphen2, SIFT, Mutation Taster). We identified two novel heterozygous missense variations in two unrelated patients, p.Arg231Gln and p.Arg226Leu, located in the repressor domain of the protein. Both variations affect highly conserved amino acids of the Gli2 protein and were not found in the available databases. In silico tools suggest that these variations might be disease causing. Our study suggests that the GLI2 gene may be one of the candidate genes to analyze when an association of pituitary hormone deficiency and developmental defects in posterior pituitary gland. The highly variable phenotype found suggests the presence of additional unknown factors that could contribute to the phenotype observed in these patients.

Mutaciones heterocigotas en el gen GLI2 fueron previamente comunicadas como causa de déficit aislado de hormona de crecimiento (IGHD) o déficit múltiple de hormonas hipofisarias (MPHD), con o sin otras malformaciones. El objetivo del estudio fue analizar la presencia de alteraciones en el gen GLI2 en un grupo de pacientes con IGHD o MPHD acompañado de neurohipófisis ectópica o ausente. La secuencia codificante y las regiones intrónicas flanqueantes del gen GLI2 fueron amplificadas y secuenciadas de manera directa a partir de ADN genómico extraído de sangre periférica proveniente de 18 sujetos afectados y sus familiares. Se utilizaron herramientas informáticas para predecir el impacto funcional de las nuevas variantes encontradas (Polyphen2, SIFT, Mutation Taster). Identificamos dos nuevas variantes heterocigotas con pérdida de sentido en dos pacientes no relacionados, p.Arg231Gln y p.Arg226Leu, localizadas en el dominio represor de la proteína. Estas variantes afectan aminoácidos altamente conservados en la secuencia proteica de GLI2 y no se encuentran informadas en las bases de datos disponibles. Las herramientas informáticas utilizadas sugieren que estas variantes pueden ser la causa del desarrollo de la enfermedad. Nuestro resultados indican que el gen GLI2 es uno de los genes candidatos a estudiar cuando existe una asociación entre déficit de hormonas hipofisarias y alteraciones en el desarrollo de la neurohipófisis. Se sugiere la existencia de otros factores adicionales que podrían contribuir a la variabilidad del fenotipo observado.

Three novel IGF1R mutations in microcephalic patients with prenatal and postnatal growth impairment.

BACKGROUND: IGF1R gene mutations have been associated with varying degrees of intrauterine and postnatal growth retardation, and microcephaly. OBJECTIVE: To identify and characterize IGF1R gene variations in a cohort of 28 Argentinean children suspected of having IGF-1 insensitivity, who were selected on the basis of the association of pre/postnatal growth failure and microcephaly. METHODS: The coding sequence and flanking intronic regions of IGF1R gene were amplified and directly sequenced. Functional characterization was performed by two in vitro assays: 1) [Methyl-(3) H] thymidine incorporation into DNA in fibroblast cell primary cultures from patients and controls treated with IGF-1 for 16-24 h. 2) PI3K/Akt pathway was evaluated with phospho-Akt (Ser473) STAR ELISA Kit (Millipore) in fibroblast cultures from patients and controls stimulated with IGF-1 for 10 min. Prepubertal clinical and GH-IGF-1 axis evaluation was followed up. RESULTS: We identified three novel heterozygous missense mutations in three unrelated patients, de novo p.Arg1256Ser, de novo p.Asn359Tyr and p.Tyr865Cys. In control cells, proliferation assay showed that IGF-1 significantly induced DNA synthesis at 20 h and Akt phosphorylation assay that it significantly stimulated phosphorylation after 10 min (P < 0·05 by anova and Bonferroni Tests). However, no significant increase was observed in any of the three patient fibroblasts in both functional studies. GH therapy growth response in two patients was inconsistent. CONCLUSION: These variations led to failure of the IGF1R function causing pre- and postnatal growth retardation and microcephaly. Microcephaly should be considered in the evaluation of SGA patients, because it seems to favour the frequency of detection of IGF1R mutations.

Five new cases of 46,XX aromatase deficiency: clinical follow-up from birth to puberty, a novel mutation, and a founder effect.

CONTEXT: Aromatase is the key enzyme for estrogen biosynthesis and is encoded by the CYP19A1 gene. Since 1991, several molecular CYP19A1 gene alterations associated with aromatase deficiency have been described in both sexes. OBJECTIVE: The objective of the study was to detect CYP19A1 mutations in five aromatase-deficient 46,XX patients, to describe the clinical follow-up from birth to puberty and to perform haplotype analysis associated with the high-frequency c.628G>A splice mutation in Argentinean patients. DESIGN: The design of the study was the sequencing of the coding and flanking intronic regions of the CYP19A1 gene in all patients and parents. Haplotype analysis of patients carrying the c.628G>A mutation was also performed. PATIENTS: Clinical and biochemical findings in five new cases and one previously reported female aromatase-deficient patient (46,XX) are described. All patients presented with ambiguous genitalia at birth. Congenital adrenal hyperplasia due to 21-hydroxylase deficiency as well as other steroidogenic defects were ruled out. RESULTS: Phenotypic variability among the affected patients was found during follow-up. Direct sequencing of the CYP19A1 gene from genomic DNA revealed one novel mutation (c.574C>T) in two patients. In silico analysis predicted the c.574C>T mutation to be probably damaging. Four of six nonrelated patients presented with the c.628G>A splice mutation. Haplotype analysis showed that the c.628G>A splice mutation is associated with the same haplotype in our population. CONCLUSIONS: Increased knowledge on phenotypical variability found in female aromatase-deficient patients is useful to improve the detection rate in this disorder. In our population, a genetic founder defect has probably contributed to an increase in the incidence of the c.628G>A splice mutation.

A novel missense mutation in the HSD3B2 gene, underlying nonsalt-wasting congenital adrenal hyperplasia. new insight into the structure-function relationships of 3ß-hydroxysteroid dehidrogenase type II.

CONTEXT: 3ßHSD2 is a bifunctional microsomal NAD+-dependent enzyme crucial for adrenal and gonad steroid biosynthesis, converting Δ5-steroids to Δ4-steroids. 3ßHSD2 deficiency is a rare cause of congenital adrenal hyperplasia caused by recessive loss-of-function HSD3B2 mutations. OBJECTIVE: The aim was to define the pathogenic consequences of a novel missense mutation in the HSD3B2 gene. PATIENT: We report a 7-month-old 46,XX girl referred because of precocious pubarche and postnatal clitoromegaly. Hormonal profile showed inadequate glucocorticoid levels, increased 17OHP and renin levels, and very high DHEAS levels, suggestive of compensated nonsalt-losing 3ßHSD2 deficiency. DESIGN AND RESULTS: Direct sequencing revealed a novel, homozygous, pG250V HSD3B2 mutation. In vitro analysis in intact COS-7 cells showed impaired enzymatic activity for the conversion of pregnenolone to progesterone and dehydroepiandrosterone to androstenedione (20% and 27% of WT at 6 h, respectively). G250V-3ßHSD2 decreased the Vmax for progesterone synthesis without affecting the Km for pregnenolone. Western blot and immunofluorescence suggested that p.G250V mutation has no effect on the expression and intracellular localization of the mutant protein. Molecular homology modeling predicted that mutant V250 affected an L239-Q251 loop next to a ß-sheet structure in the NAD+-binding domain. CONCLUSIONS: We identified a novel p.G250V mutation of HSD3B2 which causes an incomplete loss of enzymatic activity, explaining the compensated nonsalt loss phenotype. In vitro and in silico experiments provided insight into the structure-function relationship of the 3ßHSD2 protein suggesting the importance of the L239-Q251 loop for the catalytic activity of the otherwise stable 3ßHSD2 enzyme.