[Partial trisomy 18q due to maternal reciprocal translocation 4;18]. / Trisomía 18q parcial derivada de translocación recíproca 4;18 materna.

We report a new case of partial trisomy 18q due to a balanced reciprocal translocation 4;18 in the mother. The female infant had a partial trisomy of the long arm of chromosome 18 associated with a partial monosomy of distal 4q. The infant showed many of the main clinical features of trisomy 18, such as dysmorphic face, congenital heart defect, crossing of the second and fifth fingers over the third and fourth with flexion contractures, and abnormal genitalia. We believe that the trisomy 18 phenotype requires a large region of 18q and that the greater the trisomic fragment, the more severe the expression. We stress the importance of genetic counseling to carriers of balanced translocations. The risk for each case should be evaluated and information should be given on the possibility of prenatal diagnosis.

[Etiologic distribution of children with congenital defects]. / Distribución etiológica de los niños con defectos congénitos.

INTRODUCTION: Although it has been generally admitted that we know the cause of congenital malformations in about 40% of the cases, these data are based on very few studies. PATIENTS AND METHODS: Here we present the distribution of 22,784 malformed infants in our country by type of cause of their defects. RESULTS: Our results show a great impact of chromosomal alterations in causing congenital anomalies. On the other hand, performing the chromosomal study will enable the diagnosis of genetic entities, as well as environmental ones that are clinically similar to the clinical patterns produced by chromosomal abnormalities. CONCLUSIONS: We can recognize the cause of congenital defects in a proportion higher than the 40% which is generally accepted. Nowadays, there is no reason that justifies not performing a chromosomal study with high resolution band techniques in infants with congenital defects.