RESUMEN
3p deletion syndrome is a rare disorder involving developmental delay, dysmorphic physical features, and growth retardation. Molecular mapping of several cases in the literature have identified a critical region on chromosome 3p26. We present a child patient with characteristic features of 3p deletion syndrome and a de novo unbalanced translocation involving chromosomes 3 and 13. Fine mapping of this rearrangement using fluorescence in situ hybridization (FISH) and array-based comparative genomic hybridization (aCGH) revealed an unbalanced abnormality including a 4.5 Mb terminal deletion of chromosome 3p, telomeric to ITPR1 on 3p26.2, which was not previously identified with routine cytogenetic analysis. In addition, these investigations confirmed and refined the boundaries of a 26.5 Mb deletion of chromosome 13. This study confirms the minimal candidate region for 3p deletion syndrome, provides further evidence implicating haploinsufficiency of CNTN4 in the disorder, and demonstrates the utility of high-resolution investigations of rare chromosomal rearrangements.
Asunto(s)
Deleción Cromosómica , Trastornos de los Cromosomas/genética , Cromosomas Humanos Par 3/genética , Preescolar , Trastornos de los Cromosomas/patología , Cromosomas Humanos Par 13/genética , Hibridación Genómica Comparativa , Anomalías Craneofaciales/genética , Discapacidades del Desarrollo/genética , Femenino , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Deformidades Congénitas de las Extremidades/genética , Masculino , Fenotipo , Síndrome , Translocación GenéticaRESUMEN
We characterized two Y-ring microchromosomes (MC) found in an azoospermic patient with Turner stigmata (case A) and a male infant with hypospadias (case B). The karyotypes, as assessed by banding, FISH, and STRs/STSs analyses, were 46,X,r(Y).ish r(Y)(p11.3q11.222)(SRY+,DYZ3+) and 46,X,+r(Y)/45,X.ish r(Y)(p 11.2q11.2)(Xp/Yp-,SRY+,DYZ3+) respectively. In both cases, we evaluated the association of each MC with the centromere of the nearest and second nearest chromosomes in G-banded metaphases by means of measuring the intervening distance according to two criteria: < or =1 time or < or =3 times the size of the MC in each metaphase. The case A's MC was associated 84 times in 98 cells according to the latter or less strict criterion and two times in 98 cells according to the strict criterion; the corresponding values for case B were 84 and two in 95 cells respectively. The centromeric association appears to be related to centromeric attraction mediated by heterochromatin or centromere-specific proteins, the replication time, and the Rabl orientation.
Asunto(s)
Centrómero/genética , Centrómero/ultraestructura , Cromosomas Humanos Y/genética , Adulto , Cromosomas Humanos Par 18/genética , Cromosomas Humanos Par 21/genética , Cromosomas Humanos Par 22/genética , Humanos , Hipospadias/complicaciones , Cariotipificación , Masculino , Síndrome de Turner/complicaciones , Síndrome de Turner/genética , Proteínas de Unión al GTP rab5/genéticaRESUMEN
Interchange trisomy 21 by t(1:21)(p22:q22)mat: Interchange trisomy 21 by t(1;21)(p22;q22)mat was identified in a sporadic patient with Down syndrome. With a 21q22 specific probe, we observed signals on both normal 21 chromosomes and on the der. We reviewed the 23 published reports of families with reciprocal translocations leading to viable offspring with interchange trisomy 21. The breakpoints in chromosome 21 were mainly located in 21q (19/24 instances, including the present report) and in 19/23 cases the other chromosome involved in the translocation was <
Asunto(s)
Cromosomas Humanos Par 1 , Cromosomas Humanos Par 21 , Síndrome de Down/genética , Trisomía , Adulto , Femenino , Humanos , Cariotipificación , Masculino , Embarazo , Translocación GenéticaRESUMEN
We describe a female child with a ring chromosome 3, found after investigation for short stature. Her karyotype was 46,XX,r(3)(p26-q29). Her phenotype mainly differs from that of the nine patients previously reported with ring chromosome 3, by the presence of hypoplastic right thumb and bilateral coloboma of the iris.