RESUMO

BACKGROUND: Complex small supernumerary marker chromosomes (sSMCs) consist of chromosomal material derived from more than one chromosome and have been implicated in reproductive problems such as recurrent pregnancy loss. They may also be associated with congenital abnormalities in the offspring of carriers. Due to its genomic architecture, chromosome 15 is frequently associated with rearrangements and the formation of sSMCs. Recently, several different CNVs have been described at 16p11.2, suggesting that this region is prone to rearrangements. RESULTS: We detected the concomitant occurrence of partial trisomy 15q and 16p, due to a complex sSMC, in a 6-year-old girl with clinical phenotypic. The karyotype was analyzed by G and C banding, NOR staining, FISH and SNP array and defined as 47,XX,+der(15)t(15;16)(q13;p13.2)mat. The array assay revealed an unexpected complex sSMC containing material from chromosomes 15 and 16, due to an inherited maternal translocation (passed along over several generations). The patient's phenotype included microsomia, intellectual disability, speech delay, hearing impairment, dysphagia and other minor alterations. DISCUSSION: This is the first report on the concomitant occurrence of partial trisomy 15q and 16p. The wide range of phenotypes associated with complex sSMCs represents a challenge for genotype-phenotype correlation studies, accurate clinical assessment of patients and genetic counseling.

RESUMO

A atresia do intestino delgado é malformação congênita, conhecida como causa comum de obstrução intestinal no período neonatal. A atresia duodenal familiar é extremamente rara e tem sido atribuída a aberrações cromossômicas e a consaguinidade, sugerindo herança autossômica recessiva. As anomalias intestinais distais, como a atresia jejunoileal,são malformações congênitas raras do intestino delgado e têm sido relacionadas a oclusões vasculares tanto no início quanto no final da gestação além de causas genéticas. A atresia jejunoileal familiar em gêmeos é de ocorrência extremamente rara e é relacionada a algumas drogas e tinturas que são instiladas durante a gestação para diagnósticopor amniocentese e tem sido descrita como causa da atresia jejunoileal em irmãos gêmeos. Autores de dois diferentes estudos descrevem que esta atresia é significantemente mais frequente em gêmeos que em irmãos nascidos separadamente. No presente artigo descrevemos dois casos extremamente raros em dois irmãos nascidos com três anosde diferença, ambos com atresia jejunoileal sem outras malformações associadas ou anomalias cromossômicas, que foram acompanhados pela equipe em 2004 e 2007, respectivamente. Apesar das investigações, não foram encontradas nenhuma razão para essa ocorrência. Contudo, os autores estão seguindo os dois meninos desde então e não detectaramalterações no desenvolvimento de nenhum deles que pudessem sugerir qualquer malformação associada.

Small intestinal atresia is a common congenital malformation and it is a well-known cause of intestinal obstruction in neonates. Familial occurrence of duodenal atresia is extremely rare and has been attributed to chromosomal aberrations and parental consanguinity suggesting autosomal recessive inheritance. Distal intestinal anomalies, such as jejunoileal atresia, are a rare congenital malformation of the small bowel and have been related to vascular occlusion in the earlier or later stages in pregnancy and genetic causes. Familial jejunoileal atresia in twins is an extremely rareoccurrence that is attributed to the use of some chemicals and other dyes instillated during diagnostic amniocentesis and has been described as a cause of jejunoileal atresia in twin-brothers. Authors of two different research institutes stated that jejunoileal atresia is significantly more frequent in twins than in singletons. In the present article we describean extremely rare occurrence in two singleton infants, who were born three years apart, with similar jejunoileal atresia with no other associated malformations or chromosomal anomalies, who were treated in 2004 and 2007, respectively. Despite investigation, we did not find any reason for this particular occurrence; however they will be closely followed inorder to detect any development alterations that could indicate an associated malformation.