Familial translocation t(10;14) (q26.1;q32.3): report of three offspring with 10q deletion and 14q duplication

We describe two brothers and a cousin with common clinical features, including mild mental retardation, motor delays, hypotonia with truncal ataxia, esotropia, and mild facial and hand dysmorphia. The initial routine chromosome study failed to detect any abnormality in the proband. Based on a high index of clinical suspicion, high-resolution chromosome studies were performed on the proband's parents. A small reciprocal translocation t(10;14) (q26.1;q32.3) was detected in the father. The breakpoint on the derivative chromosome 14 was further placed telomeric to the immunoglobulin heavy-chain gene cluster at the band q32.33 by fluorescence in situ hybridization. Studies of the proband and two affected paternal cousins revealed that each had inherited the same derivative chromosome 10 from their carrier parents. This unbalanced karyotype resulted from an adjacent-1 segregation of the 10;14 translocation.     

Monosomy 10qter due to a balanced familial translocation: t(10;16)(q25.2;q24)

A third case of monosomy 10q is described. The infant was severely malformed and died at day 9 post partum. The clinical symptoms are compatible with the two previous cases.     

Chromosome 7q22‐q31 duplication: Report of a new case and review

We report on a girl with psychomotor retardation, growth retardation, microcephaly, frontal bossing, large ears, small nose, high arched and narrow palate, short neck, and generalized hirsutism. Cytogenetic analysis in addition to fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) showed the presence of a chromosome 7q22→q31.3 duplication. Comparison with other reported cases shows some resemblance but insufficient to enable us to establish a definite syndrome with specific clinical manifestations. The importance in better analyzing further cases by new molecular cytogenetics techniques is raised. Am. J. Med. Genet. 95:164–168, 2000. © 2000 Wiley‐Liss, Inc.     

Chromosome 22q11 deletions are not found in autistic patients identified using strict diagnostic criteria

A group of 103 subjects with a strict diagnosis of autism were tested for deletion of band q11.2 on the long arm of chromosome 22. No deletions were found, indicating that when a patient has been diagnosed with autism using strict and consistent criteria, in the absence of other indications, it is unlikely that this individual will have a 22q11 deletion. Testing for 22q11 deletions is therefore unlikely to be necessary in these patients. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:15–17, 2000. © 2000 Wiley‐Liss, Inc.     

Unbalanced translocation 46,xy,−15,+der(22)t(15;22)(q13;q11)pat: Case report and review of the literature

We present a boy with a rare unbalanced translocation 46,XY,?15,+der(22),t(15;22)(q13;q11) pat. Previous reports of similar chromosome findings mention only the Prader-Willi phenotype. At birth, his manifestations included severe hypotonia and lethargy, (typical of deletion of 15pter→q13); hypertelorism, down-slanting small palpebral fissures, preauricular tags, long philtrum (typical of duplication of 22pter→q11); severe laryngotracheo-malacia, and proximal implantation of the thumb. In a review of the literature on chromosome abnormalities involving duplication of 22q11 the associated clinical phenotype consists of mild mental retardation, microcephaly, hypotonia, hypertelorism, down-slanting palpebral fissures, a long philtrum, cleft or highly arched palate, and ear abnormalities. Preauricular pits or tags are common. Cardiovascular defects, renal and genital problems and dislocated hips are frequently present. Anal atresia and colobomata are mainly seen in cat-eye syndrome, the phenotype associated with idic 22q11. Our findings indicate that patients with unbalanced t(15;22) can have manifestations of the dup 22q11, in addition to the previously reported Prader-Willi phenotype, even if the duplicated segment is small. © 1992 Wiley-Liss, Inc.     

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.     

Sperm analysis by FISH in a case of t(17; 22) (q11; q12) balanced translocation: case report

Individual sperm from men with balanced translocations have different chromosomal contents. Thus, an estimation of the overall sperm chromosomal imbalance of such patients could help to give the couple an adapted genetic counselling. We report here the study of a balanced translocation carrier, t(17;22) (q11;q12) whose reproductive history reported four miscarriages. Moreover, he had an abnormal semen analysis with oligoteratozoospermia. The meiotic segregation pattern was examined in 700 sperm, using fluorescence in-situ hybridization (FISH). Nineteen percent of the sperm had balanced translocations or were normal. All other sperm were unbalanced (81%) and their distribution was observed as follows: the frequencies of adjacent 1, adjacent 2 and 3:1 segregations were 12.9, 5.8 and 46.8% respectively. Among the segregations scored, 13.7% were related to second meiotic division abnormalities. Less than 2% of the total sperm scored were not explained. The 3:1 segregation was present at a very high rate, which is very unusual. In cases of balanced translocations, we believe that no general features can be drawn. Thus, the FISH technique may be very helpful for genetic counselling, which remains an important step and must be done with care.     

An unusual chromosome 22q11 deletion associated with an apparent complementary ring chromosome in a phenotypically normal woman

We report an unusual chromosome 22q11 deletion associated with an apparent complementary ring chromosome in a phenotypically normal woman with a family medical history of 22q11 deletion. Using peripheral blood samples, conventional karyotyping, Fluorescence In Situ Hybridization (FISH) analysis on metaphase spreads and oligo array-based comparative genomic hybridization (oligo array-CGH) were performed. After conventional cytogenetic examination, the chromosome formula was as follows: 47,XX,+r(?)[16]/46,XX[6]. The FISH analysis revealed that this patient had a rearranged chromosome 22 with decreased centromeric fluorescence intensity and deletion of the 22q11.2 locus. She also had a supernumerary ring chromosome composed of an alpha-satellite centromere of 22 origin and 22q11.2 locus. The oligo array-CGH profile showed a deletion of approximately 4.18?Mb on chromosome 22 with a log 2 intensity ratio mean deviation of the deleted region of about -0.29. The 22q11 deletion associated with a complementary ring chromosome described in our patient could be consistent with a centromere misdivision mechanism, with one chromosomal break occurring in the alpha-satellite array and a second one in the 22q11 locus, a mechanism which has recently been referred to as the McClintock mechanism.     

Proximal duplication of the long arm of chromosome 10 (10q11.2 → 10q22): a distinct clinical entity

This report summarizes the clinical and cytogenetic findings in a 16-year-old moderately mentally retarded girl with 10q11.2----10q22 duplication. The phenotypic findings are identical to those found in one other patient with the same autosomal duplication. These data suggest that proximal 10q11.2-10q22 duplication is associated with a specific clinically recognizable syndrome.     

Transmission of a balanced homologous t(22q;22q) translocation from mother to normal daughter

The transmission of a t(22q;22q) translocation is reported. The mother had had multiple miscarriages and carried both t(22q;22q) and t(22p;22p) portions of the rearrangement in a portion of her cells. The phenotypically normal daughter, who was the proband and was referred because of multiple miscarriages, also carried the t(22q;22q) translocation.     

Prevalence of 22q11 region deletions in patients with velopharyngeal insufficiency

Velo-cardio-facial syndrome, DiGeorge syndrome, conotruncal anomaly face syndrome, tetralogy of Fallot, and pulmonary atresia with ventricular septal defect are all associated with hemizygosity of 22q11. While the prevalence of the deletions in these phenotypes has been studied, the frequency of deletions in patients presenting with velopharyngeal insufficiency (VPI) is unknown. We performed fluorescence in situ hybridization for locus D22S75 within the 22q11 region on 23 patients with VPI (age range 5–42 years) followed in the Craniofacial Clinic at the University of Florida. The VPI occurred either as a condition of unknown cause (n=16) or as a condition remaining following primary cleft palate surgery (n=7). Six of sixteen patients with VPI of unknown cause and one of seven with VPI following surgery had a deletion in the region. This study documents a high frequency of 22q11 deletions in those presenting with VPI unrelated to overt cleft palate surgery and suggests that deletion testing should be considered in patients with VPI. Am. J. Med. Genet. 77:8–11, 1998. © 1998 Wiley-Liss, Inc.     

Autism and maternally derived aberrations of chromosome 15q

Of the chronic mental disabilities of childhood, autism is causally least well understood. The former view that autism was rooted in exposure to humorless and perfectionistic parenting has given way to the notion that genetic influences are dominant underlying factors. Still, identification of specific heritable factors has been slow with causes identified in only a few cases in unselected series. A broad search for genetic and environmental influences that cause or predispose to autism is the major thrust of the South Carolina Autism Project. Among the first 100 cases enrolled in the project, abnormalities of chromosome 15 have emerged as the single most common cause. The four abnormalities identified include deletions and duplications of proximal 15q. Other chromosome aberrations seen in single cases include a balanced 13;16 translocation, a pericentric inversion 12, a deletion of 20p, and a ring 7. Candidate genes involved in the 15q region affected by duplication and deletion include the ubiquitin-protein ligase (UBE3A) gene responsible for Angelman syndrome and genes for three GABA_A receptor subunits. In all cases, the deletions or duplications occurred on the chromosome inherited from the mother. Am. J. Med. Genet. 76:327–336, 1998. © 1998 Wiley-Liss, Inc.     

Skeletal anomalies and deformities in patients with deletions of 22q11

Skeletal anomalies in patients with a 22q11.2 deletion are reported infrequently. We report the skeletal findings in 108 patients with a 22q11.2 deletion, of whom 37 (36%) had a skeletal anomaly. Twenty-two patients (20%) had anomalies of the limbs, 7 of the upper limb, including preaxial or postaxial polydactyly. An anomaly of the lower limb was found in 16 patients, including postaxial polydactyly, clubfoot, severely overfolded toes, and 2-3 toe cutaneous syndactyly. Chest films of 63 patients were examined; 30% of them had abnormal findings, most commonly supernumerary ribs (17%) or a “butterfly” vertebral body (11%). Hypoplastic vertebrae, hemivertebrae, and vertebral coronal clefts were also noted. Thus, skeletal anomalies are not uncommon in patients with a 22q11.2 deletion and may occur more frequently than recognized previously. Am. J. Med. Genet. 72:210–215, 1997. © 1997 Wiley-Liss, Inc.     

Interstitial deletion of 10q: Clinical features and literature review

We report on a patient with interstitial deletion of 10q and compare her to 8 previously described patients, 2 of whom have chromosomal breakpoints similar to our patient. Minor anomalies including broad forehead, hypertelorism, strabismus, prominent philtrum, and “dysplastic” pinnae are present in our patient. Psychomotor retardation and hypotonia are universal findings in 10q interstitial deletion. Growth retardation, not present in our patient, is seen in some. These clinical findings are sufficiently distinct to suggest early chromosome studies. © 1992 Wiley-Liss, Inc.     

Smith-Lemli-Opitz syndrome in a female with a de novo,balanced translocation involving 7q32: Probable Disruption of an SLOS gene

A 3-month-old infant girl had manifestations of the Smith-Lemli-Opitz syndrome (SLOS) including typical positional anomalies of the limbs, apparent Hirschsprung disease, cataracts, ptosis, anteverted nares, cleft of the posterior palate, small tongue, broad maxillary alveolar ridges, and abnormally low serum cholesterol levels. Chromosomal analysis showed a de novo balanced translocation interpreted as 46,XX,t(7;20)(q32.1;q13.2). We hypothesize that the translocation breakpoint in this case interrupts one SLOS allele and that the other allele at the same locus has a more subtle mutation that was inherited from the other parent. This case, as well as cytogenetic observations in other SLOS cases, suggests that SLOS could be due to autosomal recessive mutation at a gene in 7q32. © 1994 Wiley-Liss, Inc.     

Analysis of human sperm chromosome complements from a male heterozygous for a reciprocal translocation t(11;22)(q23;q11)

A reciprocal translocation between chromosomes 11 and 22 (t(11;22)(q23;q11)) is a site-specific translocation that is of particular interest because of the propensity for 3:1 segregation of the chromosomes during meiosis. There have been no published reports of chromosomally unbalanced offspring born as a result of adjacent 1 or 2 meiotic segregations in a heterozygote for this translocation. This could be explained by a meiotic mechanism which produces only 3:1 chromosomal segregations or by differential embryonic survival in which 2:2 adjacent segregations do not produce a viable pregnancy. To distinguish between these two possibilities, sperm chromosome complements from a man heterozygous for this 11;22 translocation were studied. The human sperm chromosomes were analysed after fertilization of zona pellucida-free golden hamster eggs. All possible 2:2 (alternate, adjacent 1, adjacent 2) and 3:1 segregations were observed and these segregations occurred in approximately equal frequencies. The frequency of other chromosome abnormalities, unrelated to the translocation, did not appear to be increased. These results indicate that the 11;22 translocation does not specifically cause 3:1 disjunction of chromosomes but that this segregation of chromosomes is more likely to result in a viable pregnancy.     

Recognizable behavioral and somatic phenotype in patients with proximal interstitial 18q deletion: Report on a new affected child and follow-up on the original reported familial cases

We describe a moderately retarded boy with a chromosome 18 deletion involving the regions q11.2q12.2. His phenotype is similar to that of other reported cases of proximal interstitial deletions involving 18q. We also provide follow-up information on the first 4 cases of proximal interstitial deletion of 18q from a family with a complex chromosome rearrangement originally reported in 1974. © 1992 Wiley-Liss, Inc.