Colombia
Introducción: el síndrome de Kleefstra (KS) representa 1/200.000 casos con retraso mental. El gen KMTC2 se asocia a KS tipo 2. Se caracteriza por retraso intelectual, discapacidad motora y dimorfismo facial.Objetivo: describir un caso de KS.Métodos: masculino de 8 años, hijo de padres no consanguíneos, antecedentes familiares de epilepsia y retraso del neurodesarrollo en cuarto grado. Nació a las 40 semanas vía vaginal, STORCH negativo, infecciones de vías urinarias a repetición y amenaza de aborto, sin complicaciones al nacimiento, peso al nacer de 3220 gramos, talla de 50 cm. Hitos del neurodesarrollo con sedestación a los 24 meses, marcha a los 12 meses, no habla. Examen físico, talla de 132 cm (+0,66 DS), peso 26 kg (+0,03 DS), perímetro cefálico de 50 cm, cara delgada, nariz respingada, mancha café, afasia, no movimientos linguales, hipotonía, alteraciones en marcha, retraso en el desarrollo. RMN cerebral con hipomielinización, hiperintensidades en T2 y FLAIR supratentoriales, adelgazamiento del cuerpo calloso, quiste aracnoideo temporales variante Dandy Walker. Ecocardiograma con fosa oval fisiológica. Electromiografíanormal, potenciales evocados auditivos normales, perfil tiroideo y aminoácidos cuantitativos en orina normal, azúcares reductores en orina negativos.Resultados y Discusión: cariotipo normal 46 XY[25], hibridación genómica negativa, exoma clínico variante en gen KMT2C c11968G>A (p.Asp3990As) heterocigota VUS. Este caso comparte el retraso del neurodesarrollo, psicomotor,la afasia y la microcefalia. La variante no está reportada en bases de datos genéticas.Conclusiones: es fundamental conocer el espectro de fenotipo de KS para detectar y brindar atención oportuna.
Introduction: Kleefstra Syndrome (KS) represents 1 in 200,000 cases of intellectual disability. The KMT2C gene is associated with KS type 2. It is characterized by intellectual delay, motor disability, and facial dysmorphism.
Objective: To describe a case of KS.
Methods: An 8-year-old male, born to non-consanguineous parents, with a family history of epilepsy and developmental delay in the fourth degree. He was born at 40 weeks via vaginal delivery, with a negative STORCH screening, recurrent urinary tract infections, and a threatened miscarriage. He had no complications at birth, with a birth weight of 3,220 grams and a length of 50 cm. Developmental milestones included sitting at 24 months, walking at 12 months, and no speech. On physical examination, his height was 132 cm (+0.66 SD), weight 26 kg (+0.03 SD), head circumference 50 cm, with a slender face, upturned nose, café-au-lait spot, aphasia, no lingual movements, hypotonia, gait abnormalities, and developmental delay. Brain MRI showed hypomyelination, supratentorial T2 and FLAIR hyperintensities, thinning of the corpus callosum, and a Dandy-Walker variant arachnoid cyst in the temporal region. An echocardiogram showed a physiological foramen ovale. Electromyography was normal, as were auditory evoked potentials, thyroid profile, and quantitative amino acids in urine. Urinary reducing sugars were negative.
Results and Discussion: The patient had a normal karyotype 46 XY[25], negative genomic hybridization, and clinical exome sequencing identified a variant in the KMT2C gene c.11968G>A (p.Asp3990As) heterozygous VUS. This case shares features of developmental and psychomotor delay, aphasia, and microcephaly. The variant is not reported in genetic databases.
Conclusions: It is essential to understand the phenotypic spectrum of KS to enable early detection and provide appropriate care.
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