ABSTRACT
Los transportadores de monocarboxilatos (MCT) permiten el ingreso celular de hormonas tiroideas, especialmente en el sistema nervioso central (SNC), donde son indispensables para el neurodesarrollo. La deficiencia de MCT8 produce la combinación de hipotiroidismo en SNC e hipertiroidismo periférico, caracterizada por T3 elevada. El único tratamiento actualmente disponible es el ácido 3,3',5-triyodotiroacético (TRIAC), un análogo de hormonas tiroideas que tiene como objetivo mejorar la tirotoxicosis periférica y prevenir la progresión del deterioro neurológico. En el presente artículo, se evalúan las características clínicas, imagenológicas, bioquímicas y genéticas de 4 pacientes con deficiencia de MCT8 tratados con TRIAC hasta la fecha, las dosis utilizadas y la respuesta al tratamiento.
Monocarboxylate transporters (MCTs) allow the cellular entry of thyroid hormones, especially into the central nervous system (CNS), where they are crucial for neurodevelopment. MCT8 deficiency results in the combination of hypothyroidism in the CNS and peripheral hyperthyroidism, characterized by elevated T3 levels. The only treatment currently available is 3,3',5-triiodothyroacetic acid (TRIAC), a thyroid hormone analogue aimed at improving peripheral thyrotoxicosis and preventing the progression of neurological impairment. Here we assess the clinical, imaging, biochemical, and genetic characteristics of 4 patients with MCT8 deficiency who have received TRIAC to date, the doses used, and the response to treatment.
Subject(s)
Humans , Infant , Child , Symporters/genetics , Thyroid Hormones , Triiodothyronine , Monocarboxylic Acid Transporters/geneticsABSTRACT
Monocarboxylate transporters (MCTs) allow the cellular entry of thyroid hormones, especially into the central nervous system (CNS), where they are crucial for neurodevelopment. MCT8 deficiency results in the combination of hypothyroidism in the CNS and peripheral hyperthyroidism, characterized by elevated T3 levels. The only treatment currently available is 3,3',5-triiodothyroacetic acid (TRIAC), a thyroid hormone analogue aimed at improving peripheral thyrotoxicosis and preventing the progression of neurological impairment. Here we assess the clinical, imaging, biochemical, and genetic characteristics of 4 patients with MCT8 deficiency who have received TRIAC to date, the doses used, and the response to treatment.
Los transportadores de monocarboxilatos (MCT) permiten el ingreso celular de hormonas tiroideas, especialmente en el sistema nervioso central (SNC), donde son indispensables para el neurodesarrollo. La deficiencia de MCT8 produce la combinación de hipotiroidismo en SNC e hipertiroidismo periférico, caracterizada por T3 elevada. El único tratamiento actualmente disponible es el ácido 3,3',5-triyodotiroacético (TRIAC), un análogo de hormonas tiroideas que tiene como objetivo mejorar la tirotoxicosis periférica y prevenir la progresión del deterioro neurológico. En el presente artículo, se evalúan las características clínicas, imagenológicas, bioquímicas y genéticas de 4 pacientes con deficiencia de MCT8 tratados con TRIAC hasta la fecha, las dosis utilizadas y la respuesta al tratamiento.
Subject(s)
Symporters , Humans , Child , Symporters/genetics , Monocarboxylic Acid Transporters/genetics , Triiodothyronine , Thyroid HormonesABSTRACT
Hypothyroidism caused by Hashimoto's thyroiditis is the most common reason for thyroid dysfunction in children. Our objective was to analyze its impact on final stature in relation to height and pubertal stage at the time of diagnosis in children younger than 18 years with severe autoimmune hypothyroidism. Out of 79 patients, 78.5 % were girls. Those with goiter (56 %) had a better height at diagnosis than those without goiter (mean standard deviation score for height: 0.2 versus -2.42; p < 0.0001). Five girls (6.3 %) had precocious puberty. When considering the final stature of patients (n: 33), among those with short stature at the time of diagnosis, pubertal children had a significantly shorter final stature than prepubertal children (mean standard deviation score for height: -2.82 versus -1.52; p = 0.0311). The late diagnosis of severe hypothyroidism in pediatrics has a negative impact on final stature, especially in those who were pubertal patients at the time of diagnosis.
El hipotiroidismo por tiroiditis de Hashimoto es la causa más frecuente de disfunción tiroidea en niños. Nuestro objetivo fue analizar el impacto en la talla final según la talla y el estadio puberal al momento del diagnóstico en menores de 18 años con hipotiroidismo grave de origen autoinmune. De los 79 pacientes, el 78,5 % fueron mujeres. Los que presentaron bocio (el 56 %) mostraron mejor talla en el diagnóstico que los que no lo tenían (puntaje de desvío estándar de media de talla: 0,2 vs. -2,42; p < 0,0001). Cinco niñas (el 6,3 %) presentaron pubertad precoz. De los pacientes con talla final (n: 33), dentro de los que presentaron talla baja al momento del diagnóstico, los púberes tuvieron una talla final significativamente menor que los prepúberes (puntaje de desvío estándar media: -2,82 vs. -1,52; p = 0,0311). El diagnóstico tardío de hipotiroidismo grave en pediatría tiene un impacto negativo en la talla final, especialmente, en los pacientes puberales al momento del diagnóstico.
Subject(s)
Body Height/physiology , Growth Disorders/etiology , Hashimoto Disease/complications , Thyroiditis, Autoimmune/complications , Child , Delayed Diagnosis , Female , Goiter/epidemiology , Hashimoto Disease/diagnosis , Hashimoto Disease/etiology , Humans , Male , Outcome Assessment, Health Care , Puberty, Precocious/epidemiology , Retrospective Studies , Severity of Illness Index , Thyroiditis, Autoimmune/diagnosis , Thyroiditis, Autoimmune/etiologyABSTRACT
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.
Subject(s)
Human Growth Hormone/deficiency , Kruppel-Like Transcription Factors/genetics , Mutation, Missense , Pituitary Hormones/deficiency , Argentina , Child , Child, Preschool , Female , Heterozygote , Humans , Infant , Infant, Newborn , Introns , Male , Microcephaly/diagnosis , Phenotype , Pituitary Gland, Anterior/abnormalities , Pituitary Gland, Posterior/abnormalities , Zinc Finger Protein Gli2ABSTRACT
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.
Subject(s)
Humans , Male , Infant, Newborn , Infant , Child, Preschool , Child , Pituitary Hormones/deficiency , Human Growth Hormone/deficiency , Mutation, Missense , Kruppel-Like Transcription Factors/genetics , Phenotype , Argentina , Pituitary Gland, Anterior/abnormalities , Pituitary Gland, Posterior/abnormalities , Introns , Zinc Finger Protein Gli2 , Heterozygote , Microcephaly/diagnosisSubject(s)
Growth Disorders/blood , Human Growth Hormone/blood , Human Growth Hormone/standards , Immunoenzyme Techniques , Luminescent Measurements , Adolescent , Calibration , Child , Child, Preschool , Female , Growth Disorders/diagnosis , Human Growth Hormone/deficiency , Humans , Infant , Linear Models , Male , Protein Isoforms/blood , Protein Isoforms/standards , Recombinant Proteins/blood , Recombinant Proteins/standards , Reference Standards , Reference Values , Retrospective StudiesABSTRACT
BACKGROUND: Establishment of reliable reference intervals remains valuable for confirming validity and advancing standardization across methods and populations. Moreover, knowledge of the measurement uncertainty (U) and of the reference change value (RCV) has important applications in clinical chemistry. METHODS: Starting from the information available in the laboratory data base (29,901 subjects) an initial selection was carried out by eliminating all subjects with a clinical or laboratory pathological report; data from 7581 0- to 20-year-old subjects (53.87% girls) remained in the study. These subjects, divided into nine age groups, were used to define reference distribution percentiles (2.5th, 50th and 97.5th) of serum thyrotropin (TSH), triiodothyronine (T3), thyroxine (T4), and free T4 (fT4), as well as U and RCV of these assays. RESULTS: In early infancy, T4 and fT4 values were higher than in the older age groups. Serum T4 95th percentile reference value, useful for the diagnosis of hyperthyroidism, was 142.9 in 20-year-old boys and 230.4 nmol/L in early infants and serum T3 95th percentile was 2.6 and 3.5 nmol/L, respectively, while fT4 2.5th percentile reference value, useful for the diagnosis of hypothyroidism, was 9.6 and 13.0 pmol/L, respectively. Serum TSH 97.5th percentile showed less age variation, 4.38-4.88 mIU/L. Performance of the four assays resulted in approximately 20% Us, reflecting simple and complex imprecision, trueness, analytical and functional sensitivity. RCV of serum TSH (58.6%) was larger than for thyroid hormones (28.3%-34.7%), probably due to the high biological variation of this hormone. CONCLUSIONS: We have established reference interval for TSH and thyroid hormones, as well as Us for assessing reliability of measurements, and RCVs to alert users on the presence of clinical significant changes.
