Genotype-Phenotype Correlations in Central Precocious Puberty Caused by MKRN3 Mutations.

CONTEXT: Loss-of-function mutations of makorin RING finger protein 3 (MKRN3) are the most common monogenic cause of familial central precocious puberty (CPP). OBJECTIVE: To describe the clinical and hormonal features of a large cohort of patients with CPP due to MKRN3 mutations and compare the characteristics of different types of genetic defects. METHODS: Multiethnic cohort of 716 patients with familial or idiopathic CPP screened for MKRN3 mutations using Sanger sequencing. A group of 156 Brazilian girls with idiopathic CPP (ICPP) was used as control group. RESULTS: Seventy-one patients (45 girls and 26 boys from 36 families) had 18 different loss-of-function MKRN3 mutations. Eight mutations were classified as severe (70% of patients). Among the 71 patients, first pubertal signs occurred at 6.2 ±â€…1.2 years in girls and 7.1 ±â€…1.5 years in boys. Girls with MKRN3 mutations had a shorter delay between puberty onset and first evaluation and higher follicle-stimulating hormone levels than ICPP. Patients with severe MKRN3 mutations had a greater bone age advancement than patients with missense mutations (2.3 ±â€…1.6 vs 1.6 ±â€…1.4 years, P = .048), and had higher basal luteinizing hormone levels (2.2 ±â€…1.8 vs 1.1 ±â€…1.1 UI/L, P = .018) at the time of presentation. Computational protein modeling revealed that 60% of the missense mutations were predicted to cause protein destabilization. CONCLUSION: Inherited premature activation of the reproductive axis caused by loss-of-function mutations of MKRN3 is clinically indistinct from ICPP. However, the type of genetic defect may affect bone age maturation and gonadotropin levels.

Novel Genetic and Biochemical Findings of DLK1 in Children with Central Precocious Puberty: A Brazilian-Spanish Study.

BACKGROUND: Central precocious puberty (CPP) has been associated with loss-of-function mutations in 2 paternally expressed genes (MKRN3 and DLK1). Rare defects in the DLk1 were also associated with poor metabolic phenotype at adulthood. OBJECTIVE: Our aim was to investigate genetic and biochemical aspects of DLK1 in a Spanish cohort of children with CPP without MKRN3 mutations. PATIENTS: A large cohort of children with idiopathic CPP (Spanish PUBERE Registry) was studied. Genomic deoxyribonucleic acid was obtained from 444 individuals (168 index cases) with CPP and their close relatives. Automatic sequencing of MKRN3 and DLK1 genes were performed. RESULTS: Five rare heterozygous mutations of MKRN3 were initially excluded in girls with familial CPP. A rare allelic deletion (c.401_404 + 8del) in the splice site junction of DLK1 was identified in a Spanish girl with sporadic CPP. Pubertal signs started at 5.7 years. Her metabolic profile was normal. Familial segregation analysis showed that the DLK1 deletion was de novo in the affected child. Serum DLK1 levels were undetectable (<0.4 ng/mL), indicating that the deletion led to complete lack of DLK1 production. Three others rare allelic variants of DLK1 were also identified (p.Asn134=; g.-222 C>A and g.-223 G>A) in 2 girls with CPP. However, both had normal DLK1 serum levels. CONCLUSION: Loss-of-function mutations of DLK1 represent a rare cause of CPP, reinforcing a significant role of this factor in human pubertal timing.

Engrosamiento del tallo hipofisario en niños y adolescentes con diabetes insípida central: causas y consecuencias / Thickening of the pituitary stalk in children and adolescents with central diabetes insipidus: Causes and consequences

Introducción: La diabetes insípida central (DIC) es una entidad poco frecuente en la edad pediátrica, siendo su etiología heterogénea. El objetivo de nuestro trabajo es demostrar que el seguimiento clínico y neurorradiológico de la región hipotálamo-hipofisaria, puede ayudar a establecer el diagnóstico etiológico de DIC y la presencia de otros déficits hormonales. Métodos: Se revisaron de forma retrospectiva 15 pacientes diagnosticados de DIC en un hospital pediátrico. Se analizaron las características clínicas y auxológicas; así como la valoración de la función adenohipofisaria junto con RM craneal de manera periódica. Resultados: La mediana de edad al diagnóstico fue de 9,6 años (rango: 1,3-15,9). El diagnóstico etiológico pudo establecerse en 9 de los 15 pacientes (germinomas: 7 e histiocitosis: 2). Tras una mediana de seguimiento de 5,5 años (rango: 1,6-11,8), los casos idiopáticos se redujeron a la mitad. Finalmente, los diagnósticos etiológicos fueron: germinoma 9 (60%), histiocitosis 3 (20%) y DIC idiopática 3 (20%). Existe una asociación estadísticamente significativa entre el engrosamiento del tallo y la etiología tumoral. El 67% desarrolló, al menos, una deficiencia hormonal adenohipofisaria, la mayoría en los dos primeros años de seguimiento. El déficit más prevalente fue el de hormona de crecimiento (60%). Conclusiones: En todos los pacientes con DIC se deberá realizar un control auxológico y hormonal, con especial atención, por su frecuencia, a la deficiencia de GH, y en aquellos con DIC idiopática se debería incluir una RM semestral, al menos durante los 2-3 primeros años después del diagnóstico, pues en nuestro estudio el 50% fueron diagnosticados de germinomas o histiocitosis en este periodo

Background: Central diabetes insipidus (CDI) is a rare disorder in children. The aetiology of CDI in childhood is heterogeneous. The aim of this study is to illustrate the importance of a careful clinical and neuro-radiological follow-up of the pituitary and hypothalamus region in order to identify the aetiology and the development of associated hormonal deficiencies. Methods: Clinical and auxological variables of 15 children diagnosed with CDI were retrospectively analysed in a paediatric hospital. Evaluations of adenohypophyseal function and cranial MRI were performed periodically. Results: The mean age at diagnosis of CDI was 9.6 years (range: 1.32-15.9). The aetiological diagnosis could be established initially in 9 of the 15 patients, as 7 with a germinoma and 2 with a histiocytosis. After a mean follow-up of 5.5 years (range: 1.6-11.8), the number of idiopathic cases was reduced by half. At the end of the follow-up, the aetiological diagnoses were: 9 germinoma (60%), 3 histiocytosis (20%), and 3 idiopathic CDI (20%). There is a statistically significant association between stalk thickening and tumour aetiology. At least one adenohypophyseal hormonal deficiency was found in 67% of cases, with the majority developing in the first two years of follow-up. Growth hormone deficiency (60%) was the most prevalent. Conclusion: The follow-up of CDI should include hormone evaluation with special attention, due to its frequency, to GH deficiency. In addition, a biannual MRI in an idiopathic CDI should be performed, at least during the first 2-3 years after diagnosis, as 50% of them were diagnosed with a germinoma or histiocytosis during this period

[Thickening of the pituitary stalk in children and adolescents with central diabetes insipidus: Causes and consequences]. / Engrosamiento del tallo hipofisario en niños y adolescentes con diabetes insípida central: causas y consecuencias.

BACKGROUND: Central diabetes insipidus (CDI) is a rare disorder in children. The aetiology of CDI in childhood is heterogeneous. The aim of this study is to illustrate the importance of a careful clinical and neuro-radiological follow-up of the pituitary and hypothalamus region in order to identify the aetiology and the development of associated hormonal deficiencies. METHODS: Clinical and auxological variables of 15 children diagnosed with CDI were retrospectively analysed in a paediatric hospital. Evaluations of adenohypophyseal function and cranial MRI were performed periodically. RESULTS: The mean age at diagnosis of CDI was 9.6 years (range: 1.32-15.9). The aetiological diagnosis could be established initially in 9 of the 15 patients, as 7 with a germinoma and 2 with a histiocytosis. After a mean follow-up of 5.5 years (range: 1.6-11.8), the number of idiopathic cases was reduced by half. At the end of the follow-up, the aetiological diagnoses were: 9 germinoma (60%), 3 histiocytosis (20%), and 3 idiopathic CDI (20%). There is a statistically significant association between stalk thickening and tumour aetiology. At least one adenohypophyseal hormonal deficiency was found in 67% of cases, with the majority developing in the first two years of follow-up. Growth hormone deficiency (60%) was the most prevalent. CONCLUSION: The follow-up of CDI should include hormone evaluation with special attention, due to its frequency, to GH deficiency. In addition, a biannual MRI in an idiopathic CDI should be performed, at least during the first 2-3 years after diagnosis, as 50% of them were diagnosed with a germinoma or histiocytosis during this period.

[Dietetic treatment with fructose in a 5-year-old girl with recurrent D-lactic acidosis]. / Tratamiento dietético con fructosa en una niña de 5 años con acidosis D-láctica recurrente.

D-lactic acidosis is an infrequent complication, mainly reported in patients with short bowel syndrome. It is characterized by recurrent episodes of encephalopathy with elevated serum D-lactic acid, usually associating metabolic acidosis. The presence of D-lactate-producing bacteria is necessary for the development of this complication. Other factors, such as the ingestion of large amounts of carbohydrates or reduced intestinal motility, contribute to D-lactic acidosis. We report a case of recurrent D-lactic acidosis in a 5-year-old girl with short bowel syndrome, due to a midgut volvulus. She initially received oral antibiotics in order to treat bacterial overgrowth, together with oral carbohydrates restriction. Nevertheless, recurrences did occur. Subsequently, 25% of the enteral nutrition was replaced for a formula containing fructose exclusively, while other fermentable sugars were restricted from the diet. After 16 years of follow up, further recurrences of D-lactic acidosis were not observed.

Cariotipo 48, XXXY/49, XXXXY y sinóstosis radioulnar proximal / Karyptype 48, XXXY/49, XXXXY and proximal radioulnar synostosis

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Tratamiento dietético con fructosa en una niña de 5 años con acidosis D-láctica recurrente / Dietetic treatment with fructose in a 5-year-old girl with recurrent D-lactic acidosis

La acidosis D-láctica es una patología infrecuente, habitualmente descrita en pacientes con síndrome de intestino corto. Se caracteriza por episodios recurrentes de encefalopatía con D-lactato sérico elevado y, generalmente, acidosis metabólica. Para su desarrollo es necesario el sobrecrecimiento de bacterias productoras de D-lactato en el colon. Otros factores, como la ingesta abundante de carbohidratos o la disminución de la motilidad intestinal, pueden favorecer una acidosis D-láctica. Presentamos un caso clínico de acidosis D-láctica recurrente en una niña de cinco años con síndrome de intestino corto secundario a un vólvulo de intestino medio. Recibió tratamiento antibiótico para el sobrecrecimiento bacteriano y restricción de carbohidratos enterales, pese a lo cual presentó recurrencias. Posteriormente, se sustituyó un 25% de su fórmula de nutrición enteral por otra con aporte exclusivo de fructosa, y se restringieron los aportes de otros azúcares fermentables. La evolución a los 16 años ha sido satisfactoria, sin presentar nuevas recurrencias

D-lactic acidosis is an infrequent complication, mainly reported in patients with short bowel syndrome. It is characterized by recurrent episodes of encephalopathy with elevated serum D-lactic acid, usually associating metabolic acidosis. The presence of D-lactate-producing bacteria is necessary for the development of this complication. Other factors, such as the ingestion of large amounts of carbohydrates or reduced intestinal motility, contribute to D-lactic acidosis. We report a case of recurrent D-lactic acidosis in a 5-year-old girl with short bowel syndrome, due to a midgut volvulus. She initially received oral antibiotics in order to treat bacterial overgrowth, together with oral carbohydrates restriction. Nevertheless, recurrences did occur. Subsequently, 25% of the enteral nutrition was replaced for a formula containing fructose exclusively, while other fermentable sugars were restricted from the diet. After 16 years of follow up, further recurrences of D-lactic acidosis were not observed

Braquidactilia tipo C debida a mutación de parada en el gen GDF5 / Brachydactyly type C due to a nonsense mutation in the GDF5 gene

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