Heterozygous aggrecan variants are associated with short stature and brachydactyly: Description of 16 probands and a review of the literature

[EN]Objective: Mutations in the aggrecan gene (ACAN) have been identified in two autosomal dominant skeletal dysplasias, spondyloepiphyseal dysplasia, Kimberley type (SEDK), and osteochondritis dissecans, as well as in a severe recessive dysplasia, spondyloepimetaphyseal dysplasia, aggrecan type. Next-generation sequencing (NGS) has aided the identification of heterozygous ACAN mutations in individuals with short stature, minor skeletal defects and mild facial dysmorphisms, some of whom have advanced bone age (BA), poor pubertal spurt and early growth cessation as well as precocious osteoarthritis

Guía de actuación en las anomalías de la diferenciación sexual (ADS) / desarrollo sexual diferente (DSD)

Las anomalías de la diferenciación sexual (ADS) engloban un amplio espectro de discordancias entre los criterios cromosómico, gonadal y fenotípico (genital) que definen la diferenciación sexual; actualmente, se aboga por la denominación de «desarrollo sexual diferente» (DSD). Su origen es congénito; se clasifican en función de los cromosomas sexuales presentes en el cariotipo; las causas genéticas conocidas son muy diversas y heterogéneas, aunque algunos casos pueden ser secundarios a factores maternos o medioambientales. Su diagnóstico y tratamiento requieren siempre una atención médica y psicosocial multidisciplinar. El diagnóstico etiológico precisa la interacción entre las exploraciones clínicas, bioquímicas (hormonales), genéticas, de imagen y, eventualmente, quirúrgicas. El tratamiento debe abordar la asignación de género, la posible necesidad de tratamiento hormonal substitutivo (suprarrenal si hay insuficiencia suprarrenal y con esteroides sexuales si hay insuficiencia gonadal a partir de la edad puberal), la necesidad de intervenciones quirúrgicas sobre las estructuras genitales (actualmente se tiende a diferirlas) y/o sobre las gónadas (en función de los riesgos de malignización), la necesidad de apoyo psicosocial y, finalmente, una adecuada programación de la transición a la atención médica en las especialidades de adultos. Las asociaciones de personas afectadas tienen un papel fundamental en el apoyo a familias y la interacción con los medios profesionales y sociales. La utilización de Registros y la colaboración entre profesionales en Grupos de Trabajo de sociedades médicas nacionales e internacionales es fundamental para avanzar en mejorar los medios diagnósticos y terapéuticos que precisan los DSD.Disorders of Sex Development (DSD) include a wide range of anomalies among the chromosomal, gonadal, and phenotypic (genital) characteristics that define sexual differentiation. At present, a definition as Different Sexual Development (DSD) is currently preferred. They originate in the pre-natal stage, are classified according to the sex chromosomes present in the karyotype. The known genetic causes are numerous and heterogeneous, although, in some cases, they may be secondary to maternal factors and/or exposure to endocrine-disrupting chemicals (EDCs). The diagnosis and treatment of DSD always requires multidisciplinary medical and psychosocial care. An aetiological diagnosis needs the interaction of clinical, biochemical (hormonal), genetic, imaging and, sometimes, surgical examinations. The treatment should deal with sex assignment, the possible need for hormone replacement therapy (adrenal if adrenal function is impaired, and with sex steroids from pubertal age if gonadal function is impaired), as well as the need for surgery on genital structures (currently deferred when possible) and/or on gonads (depending on the risk of malignancy), the need of psychosocial support and, finally, an adequate organisation of the transition to adult medical specialties. Patient Support Groups have a fundamental role in the support of families, as well as the interaction with professional and social media. The use of Registries and the collaboration between professionals in Working Groups of national and international medical societies are crucial for improving the diagnostic and therapeutic tools required for the care of patients with DSD

Pubertad precoz y tardía

La pubertad es un proceso complejo secundario a la activación y maduración del eje hipotálamo-hipófiso-gonadal (HHG). En su desarrollo intervienen factores genéticos y ambientales. La causa más frecuente de pubertad precoz (PP) es la activación del eje HHG o pubertad precoz central (PPC), existiendo una PP periférica (PPP) por incremento de esteroides sexuales no regulados por gonadotropinas y una forma mixta de inicio periférico y desencadenamiento posterior de una PPC. La PP por la exposición temprana a niveles elevados de estrógenos puede llevar a la afectación de la talla adulta por el cierre precoz de las epífisis si el diagnóstico y el tratamiento no son precoces.A veces tiene importantes implicaciones psicológicas y sociales. El tratamiento se basa en análogos de GnRH en la PPC y en la forma mixta y terapia frenadora de la síntesis y acción de los esteroides sexuales y etiológica en la PPP. La pubertad retrasada se define como la falta de comienzo puberal a los 13 años en la niña y 14 en el varón. La causa más frecuente es el retraso constitucional que aunque finalmente se consigue una maduración sexual completa y una talla adecuada puede tener un impacto psicológico negativo. Menos frecuente es el retraso o ausencia de la pubertad secundaria a causa orgánica, genética o sindrómica, que comprende los hipogonadismos hipo o hipergonadotropos de distintas etiologías. El tratamiento, si se puede, debe ser etiológico y hay que inducir la pubertad en el varón con testosterona a dosis progresivas por vía intramuscular o subcutánea y luego mantener la virilización con testosterona en parches o gel y en la niña la inducción de la pubertad se hará con estrógenos orales o transdérmico a bajas dosis añadiendo posteriormente gestágenos cíclicos

Guía de actuación en las anomalías de la diferenciación sexual (ADS) / desarrollo sexual diferente (DSD).

Disorders of Sex Development (DSD) include a wide range of anomalies among the chromosomal, gonadal, and phenotypic (genital) characteristics that define sexual differentiation. At present, a definition as Different Sexual Development (DSD) is currently preferred. They originate in the pre-natal stage, are classified according to the sex chromosomes present in the karyotype. The known genetic causes are numerous and heterogeneous, although, in some cases, they may be secondary to maternal factors and/or exposure to endocrine-disrupting chemicals (EDCs). The diagnosis and treatment of DSD always requires multidisciplinary medical and psychosocial care. An aetiological diagnosis needs the interaction of clinical, biochemical (hormonal), genetic, imaging and, sometimes, surgical examinations. The treatment should deal with sex assignment, the possible need for hormone replacement therapy (adrenal if adrenal function is impaired, and with sex steroids from pubertal age if gonadal function is impaired), as well as the need for surgery on genital structures (currently deferred when possible) and/or on gonads (depending on the risk of malignancy), the need of psychosocial support and, finally, an adequate organisation of the transition to adult medical specialties. Patient Support Groups have a fundamental role in the support of families, as well as the interaction with professional and social media. The use of Registries and the collaboration between professionals in Working Groups of national and international medical societies are crucial for improving the diagnostic and therapeutic tools required for the care of patients with DSD

Heterozygous aggrecan variants are associated with short stature and brachydactyly: Description of 16 probands and a review of the literature.

Mutations in the aggrecan gene (ACAN) have been identified in two autosomal dominant skeletal dysplasias, spondyloepiphyseal dysplasia, Kimberley type (SEDK), and osteochondritis dissecans, as well as in a severe recessive dysplasia, spondyloepimetaphyseal dysplasia, aggrecan type. Next-generation sequencing (NGS) has aided the identification of heterozygous ACAN mutations in individuals with short stature, minor skeletal defects and mild facial dysmorphisms, some of whom have advanced bone age (BA), poor pubertal spurt and early growth cessation as well as precocious osteoarthritis. This study involves clinical and genetic characterization of 16 probands with heterozygous ACAN variants, 14 with short stature and mild skeletal defects (group 1) and two with SEDK (group 2). Subsequently, we reviewed the literature to determine the frequency of the different clinical characteristics in ACAN-positive individuals. A total of 16 ACAN variants were located throughout the gene, six pathogenic mutations and 10 variants of unknown significance (VUS). Interestingly, brachydactyly was observed in all probands. Probands from group 1 with a pathogenic mutation tended to be shorter, and 60% had an advanced BA compared to 0% in those with a VUS. A higher incidence of coxa valga was observed in individuals with a VUS (37% vs 0%). Nevertheless, other features were present at similar frequencies. ACAN should be considered as a candidate gene in patients with short stature and minor skeletal defects, particularly those with brachydactyly, and in patients with spondyloepiphyseal dysplasia. It is also important to note that advanced BA and osteoarticular complications are not obligatory conditions for aggrecanopathies/aggrecan-associated dysplasias

High prevalence of variants in skeletal dysplasia associated genes in individuals with short stature and minor skeletal anomalies

[EN]Objective: Next generation sequencing (NGS) has expanded the diagnostic paradigm turning the focus to the growth plate. The aim of the study was to determine the prevalence of variants in genes implicated in skeletal dysplasias in probands with short stature and mild skeletal anomalies. Design: Clinical and radiological data were collected from 108 probands with short stature and mild skeletal anomalies. Methods: A customized skeletal dysplasia NGS panel was performed. Variants were classified using ACMG recommendations and Sherloc. Anthropometric measurements and skeletal anomalies were subsequently compared in those with or without an identified genetic defect. Results: Heterozygous variants were identified in 21/108 probands (19.4%). Variants were most frequently identified in ACAN (n = 10) and IHH (n = 7) whilst one variant was detected in COL2A1, CREBBP, EXT1, and PTPN11. Statistically significant differences (P < 0.05) were observed for sitting height/height (SH/H) ratio, SH/H ratio standard deviation score (SDS), and the SH/H ratio SDS >1 in those with an identified variant compared to those without. Conclusions: A molecular defect was elucidated in a fifth of patients. Thus, the prevalence of mild forms of skeletal dysplasias is relatively high in individuals with short stature and mild skeletal anomalies, with variants in ACAN and IHH accounting for 81% of the cases. An elevated SH/H ratio appears to be associated with a greater probability in detecting a variant, but no other clinical or radiological feature has been found determinant to finding a genetic cause. Currently, we cannot perform extensive molecular studies in all short stature individuals so detailed clinical and radiological phenotyping may orientate which are the candidate patients to obtain worthwhile results. In addition, detailed phenotyping of probands and family members will often aid variant classification

Guía de actuación en las anomalías de la diferenciación sexual (ADS) / desarrollo sexual diferente (DSD)

Las anomalías de la diferenciación sexual (ADS) engloban un amplio espectro de discordancias entre los criterios cromosómico, gonadal y fenotípico (genital) que definen la diferenciación sexual; actualmente, se aboga por la denominación de «desarrollo sexual diferente» (DSD). Su origen es congénito; se clasifican en función de los cromosomas sexuales presentes en el cariotipo; las causas genéticas conocidas son muy diversas y heterogéneas, aunque algunos casos pueden ser secundarios a factores maternos o medioambientales. Su diagnóstico y tratamiento requieren siempre una atención médica y psicosocial multidisciplinar. El diagnóstico etiológico precisa la interacción entre las exploraciones clínicas, bioquímicas (hormonales), genéticas, de imagen y, eventualmente, quirúrgicas. El tratamiento debe abordar la asignación de género, la posible necesidad de tratamiento hormonal substitutivo (suprarrenal si hay insuficiencia suprarrenal y con esteroides sexuales si hay insuficiencia gonadal a partir de la edad puberal), la necesidad de intervenciones quirúrgicas sobre las estructuras genitales (actualmente se tiende a diferirlas) y/o sobre las gónadas (en función de los riesgos de malignización), la necesidad de apoyo psicosocial y, finalmente, una adecuada programación de la transición a la atención médica en las especialidades de adultos. Las asociaciones de personas afectadas tienen un papel fundamental en el apoyo a familias y la interacción con los medios profesionales y sociales. La utilización de Registros y la colaboración entre profesionales en Grupos de Trabajo de sociedades médicas nacionales e internacionales es fundamental para avanzar en mejorar los medios diagnósticos y terapéuticos que precisan los DSD.Disorders of Sex Development (DSD) include a wide range of anomalies among the chromosomal, gonadal, and phenotypic (genital) characteristics that define sexual differentiation. At present, a definition as Different Sexual Development (DSD) is currently preferred. They originate in the pre-natal stage, are classified according to the sex chromosomes present in the karyotype. The known genetic causes are numerous and heterogeneous, although, in some cases, they may be secondary to maternal factors and/or exposure to endocrine-disrupting chemicals (EDCs). The diagnosis and treatment of DSD always requires multidisciplinary medical and psychosocial care. An aetiological diagnosis needs the interaction of clinical, biochemical (hormonal), genetic, imaging and, sometimes, surgical examinations. The treatment should deal with sex assignment, the possible need for hormone replacement therapy (adrenal if adrenal function is impaired, and with sex steroids from pubertal age if gonadal function is impaired), as well as the need for surgery on genital structures (currently deferred when possible) and/or on gonads (depending on the risk of malignancy), the need of psychosocial support and, finally, an adequate organisation of the transition to adult medical specialties. Patient Support Groups have a fundamental role in the support of families, as well as the interaction with professional and social media. The use of Registries and the collaboration between professionals in Working Groups of national and international medical societies are crucial for improving the diagnostic and therapeutic tools required for the care of patients with DSD