A 1-year-old baby with phylloid-type pigmentary mosaicism, hypotonia, ambiguous genitalia, and a positive screening test for congenital adrenal hyperplasia was referred. Previous sonograph, cytogenetics, and metabolic profile were inconclusive, therefore we performed an additional karyotype and a molecular cytogenetics studies. A mosaic karyotype 45,X/46,X,der(Y)t(Y;14) was characterized in peripheral blood. Congenital adrenal hyperplasia genes were sequenced and the results were negative. The ambiguous genitalia was the result of the special gonosomal mosaicism. The low level of trisomy 14 led to minor physical characteristics and mild mental retardation; also, Turner syndrome features can be expected rather than severe trisomy 14 stigmata.

Fragile X syndrome (FXS) is the most common cause of hereditary intellectual disability and the second most common cause of intellectual disability of genetic etiology. This complex neurodevelopmental disorder is caused by an alteration in the CGG trinucleotide expansion in fragile X mental retardation gene 1 (FMR1) leading to gene silencing and the subsequent loss of its product: fragile X mental retardation protein 1 (FMRP). Molecular diagnosis is based on polymerase chain reaction (PCR) screening followed by Southern blotting (SB) or Triplet primer-PCR (TP-PCR) to determine the number of CGG repeats in the FMR1 gene. We performed, for the first time, screening in 247 Ecuadorian male individuals with clinical criteria to discard FXS. Analysis was carried out by the Genetics Service of the Hospital de Especialidades No. 1 de las Fuerzas Armadas (HE-1), Ecuador. The analysis was performed using endpoint PCR for CGG fragment expansion analysis of the FMR1 gene. Twenty-two affected males were identified as potentially carrying the full mutation in FMR1 and thus diagnosed with FXS that is 8.1% of the sample studied. The average age at diagnosis of the positive cases was 13 years of age, with most cases from the geographical area of Pichincha (63.63%). We confirmed the familial nature of the disease in four cases. The range of CGG variation in the population was 12–43 and followed a modal distribution of 27 repeats. Our results were similar to those reported in the literature; however, since it was not possible to differentiate between premutation and mutation cases, we can only establish a molecular screening approach to identify an expanded CGG repeat, which makes it necessary to generate national strategies to optimize molecular tests and establish proper protocols for the diagnosis, management, and follow-up of patients, families, and communities at risk of presenting FXS.

Introducción: El Síndrome de Turner (ST) es una alteración cromosómica sexual causada por la ausencia parcial o completa del cromosoma X, además de mosaicismos y otras alteraciones estructurales del cromosoma X o Y; está presente en 1 de 2500 nacidas vivas. Objetivo: Describir las variantes citogenéticas de pacientes con síndrome de Turner y evaluar su asociación con el fenotipo de presentación y la edad del diagnóstico. Método: Estudio retrospectivo de corte transversal de una serie de 82 casos de síndrome de Turner. Los cariotipos fueron realizados utilizando el medio RPMI-1640; las preparaciones de cromosomas se obtuvieron utilizando técnicas estándar y se analizaron mediante bandas GTG con una resolución de 400-450 bandas, donde se contó con 20-50 metafases para reducir la probabilidad de no detección de mosaicismo. Resultados: 45 (55.6%) fueron diagnosticadas, con monosomía clásica del cromosoma X, mientras 29 (35,8%) mostraron anomalías estructurales del cromosoma X y 7 (8,6%) se asociaron a mosaicos numéricos del cromosoma X. Solo 21 (26%) pacientes fueron diagnosticadas por debajo de los 12 años, mientras el resto 60 (74%) se detectaron entre la adolescencia y la adultez. La baja estatura fue una característica universal en todos los grupos de estudio. Conclusiones: Las fórmulas cromosómicas en el síndrome de Turner pueden ser muy variadas y tener diversas implicaciones en el fenotipo; se destaca la baja talla como un criterio clínico relevante en la sospecha clínica.

Schaf-Yang Syndrome is a rare genetic condition, produced by a mutation in the MAGEL2 gene, located at the level of chromosome 15, in the Prader-Willi Syndrome region, with which it shares some physical similarity. The phenotype is variable and ranges from fetal akinesia to an important neurobehavioral phenotype and contractures of the small finger joints that are very characteristic. The gene has a maternal imprint and the phenotype will only be expressed when the mutated allele has been transmitted parentally. We present the case of a 2-and-a-half-year-old male from Ecuador, whose most prominent signs were in the beginning a marked macroglossia that gave a certain rough facial appearance, as well as bilateral camptodactyly of the 3rd and 4th fingers. The history of a previous sister who died at age 8 with a diagnosis of hypothyroidism, and clinical similarity to this new baby, led the clinical orientation to the screening of a potentially autosomal recessive condition. The genetic tests performed as part of the differential diagnosis where to pathologies such as Becwith-Wiedeman Syndrome, Mucopolysaccharidosis and Congenital Hypothyroidism. The clinical elements of this case are compared with those described in the literature with this rare genetic syndrome, and the clinical evolution of dysmorphic patterns in young children is emphasized in order to achieve a better diagnostic certainty. We emphasize the features of macroglossia as a probably expanding phenotype in this rare condition. The presentation of this clinical case shows that the factors that alter the segregation of simple mutations such as the case of the genetic imprint, found in this patient, constitute an event that hinders the interpretation of inheritance patterns and should always be taken into account in genetic counseling.