ABSTRACT
Resumen Introducción: El cromosoma 13 en anillo es una alteración citogenética infrecuente, clínicamente caracterizada por presentar retraso del crecimiento, del desarrollo psicomotor y déficit cognitivo, además de microcefalia, dismorfia facial, alteraciones genitales e hipoplasia del pulgar. Caso clínico: Paciente de 8 meses de edad evaluado por presentar talla baja, retraso del desarrollo psicomotor, microcefalia, dismorfia facial, hipospadias peneoescrotales e hipoplasia de pulgar. Se evidenció lisencefalia, hipoacusia neuroconductiva del lado derecho y comunicación interauricular tipo ostium secundum pequeña. El estudio citogenético del paciente mostró 46, XY, r (13) en 30 células analizadas. Conclusiones: Se resaltan los hallazgos clínicos que pueden orientar el diagnóstico de esta alteración cromosómica estructural infrecuente, destacando, además, la evaluación médica interdisciplinaria requerida y el adecuado asesoramiento genético familiar.
Abstract Background: Ring chromosome 13 is an infrequent cytogenetic disorder clinically characterized by growth and psychomotor development retardation, cognitive deficit, microcephaly, facial dysmorphism, genital alterations and thumb hypoplasia. Case report: A 8-month-old patient was evaluated for presenting short stature, psychomotor development delay, microcephaly, facial dysmorphism, penoscrotal hypospadias and thumb hypoplasia. Lissencephaly, neuroconductive hearing loss on the right side and small ostium secundum interatrial communication were evident. The cytogenetic study of the patient showed 46, XY, r (13) in 30 cells analyzed. Conclusions: Clinical findings that can guide the diagnosis of this infrequent structural chromosomal alteration are highlighted, as well as the interdisciplinary medical evaluation required and adequate family genetic counseling.
ABSTRACT
Aims: To report a case of ring chromosome 13 in a female child. Presentation of Case: Female, Caucasian, born in Southeast of Brazil, 6 years old. Born by cesarean section, the physical examination at 6 years and 1 month old has shown: weight of 19.100 grams and 105 centimeters tall, developmental delay, bushy eyebrows, epicanthic folds and broad nasal bridge, cardiovascular and respiratory systems were normal and no abnormalities in the limbs. Chromosome analysis was performed by GTG banding of peripheral blood and the karyotype was 46,XX,r(13)(p13q34)[97]/46,XX,dic r(13;13)(p13q34;p13q34) [3]. Analysis of 100 metaphases following G-banding revealed 97% cells with a ring chromosome 13,3% with dicentric ring chromosome of two 13s. Aneuploidy was not detected. Her parents had a normal karyotype. Discussion: Some researchers relate the clinical presentation of ring chromosome 13 with the extension of the deleted chromosomal region and instability. Others suggested that phenotypes of patients can be categorized in groups, according to the breakpoint on 13q. Conclusion: The classification of cases in groups based on breakpoints and chromosomal instability is still inaccurate, with variable phenotypes. Thus, the analysis of a greater number of cases and molecular analysis are important to establish more precise correlation between genotype and phenotype.
ABSTRACT
The clinical features of ring chromosome 13 include mental and growth retardation, CNS anomalies, facial dysmorphism, cardiac defects, genital malformations, limb anomalies, skeletal deformities and anal malformations. Although many cases of ring chromosome 13 have been reported worldwide, only 6 cases have been reported in Korea, and the latter cases were not mosaic but pure ring chromosome 13. Here we report a case with mosaic ring chromosome 13. The baby boy was born at 37 weeks of gestation by induced vaginal delivery due to intrauterine growth restriction (IUGR). He was the second baby of a 28-year-old hepatitis B carrier mother and a 32-year-old father. There was no family history of chromosomal anomalies. The baby was a symmetric IUGR with a birth weight of 1,860 g, length of 44.8 cm, and head circumference of 29.4 cm. The physical examination revealed microcephaly, trigonocephaly, flat occiput, large ears, short neck and dysmorphic facial features, including microophthalmia, hypertelorism, antimongoloid slanting palpebral fissures, a flat nasal bridge, and micrognathia. The karyotype of this patient performed by peripheral blood lymphocytes was 46,XY,r(13)(p13q34)/45,XY,-13/46,XY,dic r(13;13)(p13q34;p13q34). The baby showed failure to thrive, hypotonia, and developmental delay. We report the first case of mosaic ring chromosome 13 in a male baby in Korea and compare this case with other Korean cases of non-mosaic ring chromosome 13.