De novo translocation heterozygote with three reciprocal translocations.

An extremely rare case of a child with three balanced reciprocal translocations involving six different autosomes is described. These abnormalities have apparently arisen de novo and seem to have only relatively minor phenotypic effects. The meiotic possibilities are discussed and cytogenetic markers suggest that the damage may have occurred in a paternal gamete.     

De novo 3q/7q translocation and associated interstitial 7q35 deletion

In the present report we describe a severely mentally retarded and dysmorphic female child with a de novo 3q/7q reciprocal translocation and loss of band 7q35. This finding supports the hyothesis that the occurrence of mental retardation and/or congenital malformations in de novo autosomal reciprocal translocation may be due to the loss of a small amount of chromatin material during this chromosomal rearrangement.     

De novo 10q22 interstitial deletion

We describe a 4 month old male with a de novo interstitial deletion of chromosome 10q22. His clinical features included growth deficiency, developmental delay, ocular hypertelorism, posteriorly rotated ears, retrognathia, and fifth finger clinodactyly. He later developed dental lamina cysts of the alveolar ridge. To our knowledge, this is the first reported case of an interstitial deletion of 10q22.


Keywords: chromosome 10; interstitial deletion; deletion 10q; multiple congenital anomaly (MCA) syndrome     

A de novo translocation in a family with a balanced reciprocal chromosomal translocation

A carrier of a reciprocal translocation between chromosomes 10 and 18 had a child with a reciprocal translocation involving different segments of the same chromosomes. The categories of possible meiotic errors in carriers of balanced rearrangements must, therefore, be expanded to include new reciprocal translocations.     

De novo 16p deletion: ATR-16 syndrome

We describe a child with α-thalassemia ascertained by newborn screening. Evaluation at 9 months of age showed minor anomalies and developmental delay. Chromosomal analysis demonstrated a de novo deletion of the most distal portion of the short arm of chromosome 16, which contains the α-globin genes. Analysis of the α-globin locus by Southern blot analysis did not demonstrate altered band sizes at this locus; however, analysis of the films using densitometry confirmed hemizygosity. This is the fifth reported case of the ATR-16 syndrome (α-thalassemia retardation-16) not complicated by duplication or deletion of other chromosomes. Am. J. Med. Genet. 72:451–454, 1997. © 1997 Wiley-Liss, Inc.     

De novo reciprocal 1p;2q translocation in a child with multiple congenital anomalies/mental retardation syndrome

A newborn male infant was found to have an unusual pattern of congenital anomalies associated with an apparently balanced de novo reciprocal translocation: 46,XY,t(1;2)(p22;q22). The infant had a previously apparently undescribed multiple congenital anomalies and mental retardation syndrome.     

De novo balanced reciprocal translocation 46,XY,t(6;8)(q13;q22).

A 5-month-old infant was examined because of minor multiple malformations. He was found to have a de novo blanced reciprocal translocation 46,XY,t(6;8(q13;q22). On follow-up at the age of 17 months his mental development was found to be within normal limits.     

De novo apparently balanced reciprocal translocation between 5q1l.2 and 17q23 associated with Klippel-Feil anomaly and type A1 brachydactyly

We report on a girl with Klippel-Feil anomaly, type Al brachydactyly, and minor facial anomalies. She has an apparently balanced de novo reciprocal translocation between 5q1l.2 and 17q23. The possible significance of this chromosomal abnormality is discussed. © 1995 Wiley-Liss, Inc.     

De novo subtelomeric deletion of 15q associated with satellite translocation in a child with developmental delay and severe growth retardation

We report on a case of satellited 15q with subtelomeric deletion in a girl with delayed development and severe growth retardation. The patient also has a triangular face, downturned angles of the mouth, micrognathia, and minor limb malformations including mild talipes equinovarus, genu recurvatum, and increased dorsiflexion of both limbs. Cytogenetic analysis using standard GTG banding showed a female karyotype with a satellited-like structure at the distal long arm of one chromosome 15. Silver staining of the nucleolar organizing region (AgNOR) confirmed the presence of a satellite DNA translocation at the lesion. Analysis using fluorescent in situ hybridization (FISH) detected a subtelomeric deletion of the terminal 15q. Additional molecular analysis using microsatellite markers along the long arm of chromosome 15 defined a maximally deleted region at approximately 4.7 Mb. Haploinsufficiency of the IGF1R gene expression is thought to be the cause of growth delay in all 15q terminal deletion including our patient.     

Campomelic dysplasia associated with a de novo 2q;17q reciprocal translocation.

A phenotypically female fetus with campomelic dysplasia and a de novo reciprocal translocation, 46,XY,t(2;17) (q35;q23-24), is presented. This is the second case of campomelic dysplasia in which a rearrangement involving the long arm of chromosome 17 has been identified, indicating that this is likely to be the site of the campomelic dysplasia locus.     

De novo terminal deletion 7p22.1--pter in a child without craniosynostosis.

A patient with a de novo terminal deletion of the short arm of chromosome 7 (p22.1--pter) is described. Facial dysmorphism, a congenital heart defect, and genital hypoplasia were evident. There were no signs of craniosynostosis. Our observation confirms that deletion of 7p22 is not necessarily associated with craniosynostosis.     

De novo interstitial deletion q16.2q21 on chromosome 6

A de novo interstitial deletion of 6q16.2q21 was observed in a 23-month-old boy with mental and psychomotor delay, obese appearance, minor craniofacial anomalies, and brain anomalies. We compare clinical manifestations of this patient with those observed in previously reported cases with similar 6q interstitial deletions. It is interesting to note the clinical similarities between some patients with interstitial deletions of 6q16 or q21 bands and patients with Prader-Willi syndrome (PWS) and it may help to keep in mind cytogenetic studies of patients with some PWS findings. © 1995 Wiley-Liss, Inc.     

Diamond-Blackfan anaemia in a girl with a de novo balanced reciprocal X;19 translocation.

A 7 year old girl is described with congenital hypoplastic anaemia (Diamond-Blackfan anaemia, DBA) and an apparently balanced reciprocal translocation, 46,XX,t(X;19)(p21;q13). The girl has associated features including short stature, unilateral kidney hypoplasia, and a branchial cyst. Fluorescent in situ hybridisation (FISH) studies with 19q specific cosmids showed that the chromosome 19 breakpoint is located between the RYR1 and the XRCC11 loci spanning a physical region of 5 Mb. There is no family history of DBA and the parents and two healthy sibs have normal karyotypes. This is the first report of a balanced translocation associated with DBA and we suggest that the distinct phenotype has resulted from a de novo disruption of a functional gene. DBA can be inherited as an autosomal trait and our observation may indicate a candidate gene for the disorder in the 19q13 region.     

Acampomelic campomelic dysplasia with de novo 5q;17q reciprocal translocation and severe phenotype.

Campomelic dysplasia (CD) is a rare skeletal malformation syndrome caused by mutations in the SRY related gene SOX9, mapped to 17q24.3-q25.1. A small proportion of cases are associated with structural rearrangements involving 17q and it has been proposed that this subgroup have a milder phenotype and better prognosis compared to those with mutations in the SOX9 gene. We report a severely affected infant with the acampomelic form of campomelic dysplasia, who died at 11 days and was found to have a de novo reciprocal translocation, 46,XX,t(5;17)(q15;q25.1). This is the second reported case of severe campomelic dysplasia associated with a structural rearrangement involving 17q and suggests that this subgroup of patients may not significantly differ from those without chromosomal rearrangements with regards to phenotype or prognosis.     

De novo 7q36 deletion: Breakpoint analysis and types of holoprosencephaly

We report on a de novo 7q36 deletion in a 3-month-old girl with manifestations of the 7q terminal deletion syndrome. Only minimal findings of holoprosencephaly (HPE) were present since only a partial corpus callosum hypoplasia was seen on a magnetic resonance imaging scan of the brain. Extensive fluorescence in situ hybridization analysis showed that the HPE3 critical gene region, inclusive Sonic hedgehog (SHH), En2 (HOX1), and HTR5A, was deleted. A review of 33 other patients with a de novo terminal 7q deletion and the different types of HPE manifestations within these patients will be presented. Am. J. Med. Genet. 75:153–158, 1998. © 1998 Wiley-Liss, Inc.     

Concurrent de novo interstitial deletion of band 2p22 and reciprocal translocation (3;7)(p21;q22).

A child is described with a de novo interstitial deletion of band 2p22 and a reciprocal translocation (3;7)(p21;q22). The child has mild developmental delay, coloboma of the right eye, and Hirschsprung's disease. The clinical and cytogenetic findings are described.     

De novo translocation Down''s syndrome: Risk of recurrence of Down''s syndrome

Seventy-six cases of de novo translocation Down's syndrome had 101 siblings, none with Down's syndrome. The risk to the parents of a de novo translocation Down's syndrome child of subsequently having another child with Down's syndrome is, therefore, taken to be less than 1/101. It is emphasized that this estimate is based on a heterogeneous material. Aspects of the formation of the translocation chromosome are discussed.