De novo translocation (2;18)(q21;q22) in a child with severe epilepsy, developmental delay and mild dysmorphism

De novo translocation (2;18)(q21;q22) in a patient with severe epilepsy developmental delay and mild dysmorphism: We report on a patient presenting with severe epilepsy, hypotonia, developmental delay, blepharophimosis, low-set ears, camptodactyly and tapering fingers, and cutaneous syndactyly of toes II and III of the right foot. The MRI showed some loss of volume of the white matter and delayed myelination, no other specific anomalies were present. Chromosome analysis revealed a translocation involving chromosomes 2 and 18, which was characterized further by FISH using band-specific probes. The possibility of a submicroscopic deletion is discussed and the patient is compared with patients reported in the literature with either 2q21 or 18q22 deletion.     

Pure distal monosomy 10q26 in a patient displaying clinical features of Prader-Willi syndrome during infancy and distinct behavioural phenotype in adolescence

A male patient is reported with terminal 10q26 deletion and clinical findings suggesting Prader-Willi syndrome during the infancy. These findings included decreased fetal movements, neonatal hypotonia, need for tube feeding, characteristic facial dysmorphism with dolichocephaly, narrow bifrontal diameter, almond-shaped eyes and epicanthus, hypogenitalism and developmental retardation. However, during the further evolution there was neither hyperphagia nor obesity and chromosomal and molecular investigations failed to confirm the diagnosis of Prader-Willi syndrome. Special behavioural abnormalities became evident with notably hyperactivity, hyperkinesis and destructive tendency. Finally, at the age of 17 years high resolution chromosome studies revealed a terminal 10q26.3 deletion. A review of the literature is made on previously reported patients with either a Prader-Willi-like syndrome or a terminal 10q deletion with behavioural problems.     

An adult patient with a distal interstitial 14q deletion: clinical report and literature review

We report a patient with an interstitial 14q32.1-->q32.3 deletion and review the literature. The adult patient presented with moderate mental retardation, a friendly behavior and a non-specific phenotype. The deletion seemed to be terminal but with FISH probes appeared to be interstitial. Comparison with other 14q terminal and interstitial deletion patients reported in literature and those with a ring 14 chromosome is given.     

Molecular and clinical study of 183 patients with conotruncal anomaly face syndrome

To investigate molecular and clinical aspects of conotruncal anomaly face (CAF), we studied the correlation between deletion size and phenotype and the mode of inheritance in 183 conotruncal anomaly face syndrome (CAFS) patients. Hemizygosity for a region of 22q11.2 was found in 180 (98%) of the patients with CAFS by fluorescence in situ hybridization (FISH) using the N25(D22S75) DiGeorge critical region (DGCR) probe. No hemizygosity was found in three (2%) of the patients with CAFS by FISH using nine DiGeorge critical region probes and a SD10P1 probe (DGA II locus). None of these three patients had mental retardation and just one had nasal intonation, which was observed in almost all of the 180 CAFS patients who carried deletions (mental retardation, 92%; nasal voice, 88%). Nineteen of 143 families (13%) had familial CAFS and 16 affected parents (84%) were mothers. Although only two of the affected parents had cardiovascular anomalies, the deletion size in the 16 affected parents and their affected family members, who were studied by FISH analysis, was the same. It indicates that extragenic factors may play a role in the genesis of phenotypic variability, especially in patients with cardiovascular anomalies. No familial cases were found among CAFS patients with absent thymus/DiGeorge anomaly (DGA). Also, in all 18 CAFS patients with completely absent thymus/DGA and all 6 CAFS patients with schizophrenia, it was revealed that the deletion was longer distally. A study of the origin of the deletion using microsatellite analyses in 48 de novo patients showed that in 65% of CAFS patients it was maternal, while in 64% of DGA patients it was paternal. The findings of this study indicated that CAF was almost always associated with the deletion of 22q11.2. As well as the major features of the syndrome, other notable extracardiac anomalies were found to be susceptibility to infection, schizophrenia, atrophy or dysmorphism of the brain, thrombocytopenia, short stature, facial palsy, anal atresia, and mild limb abnormalities. Received: 5 January 1998 / Accepted: 7 March 1998     

Characterization of an interstitial deletion del(13)(q22q32) using microdissection and sequential FISH and G-banding

The objective of this study was to delineate a chromosome 13 abnormality and establish its clinical correlation by using molecular cytogenetics procedures. A newborn boy presented with clinical findings, including mild symmetric intrauterine growth retardation (IUGR), small ears with thickened helices, a scalp lesion, short fifth fingers, missing toes, and talipes equinovarus. Routine G-banding of cultured peripheral blood cells revealed that the patient had one abnormal and shortened chromosome 13, but uncertainty remained as to whether the abnormality was the result of an interstitial deletion or a translocation. Thirteen copies of G-banded abnormal chromosomes 13 were isolated with microdissection and amplified with PCR using degenerate oligonucleotide primers. Fluorescence in situ hybridization (FISH) of the PCR product to normal metaphases showed one pair of acrocentrics hybridized, more or less uniformly, along the length of the long arm with an unhybridized gap in the distal region, indicative of an interstitial deletion. Sequential FISH and G-banding of the same chromosome preparations conclusively demonstrated that the deleted segment was 13q22-q32. Four cases of del(13)(q22q32) have been previously reported. The common findings in all five cases, including the present one, are psychomotor and growth retardation, as well as hand and foot anomalies.     

Intercalary deletions of 9q]

Two interstitial deletions of different segments of 9q are reported. The first deletion (9/11q22) was seen in an 8-year-old boy with severe psychomotor retardation and descrete facial dysmorphism. The second deletion (9q32q34) was seen in a 5-month-old boy with a very peculiar cranio-facial dysmorphism including brachycephaly, frontal bossing, a deep nasal bridge, a short nose, and absence of triradii b, c and d.     

FISH-mapping of a 100-kb terminal 22q13 deletion

Both cytogenetically visible and cryptic deletions of the terminal region of chromosome 22q are associated with a clinical phenotype including mental retardation, delay in expressive speech development, hypotonia, normal to accelerated growth and minor facial dysmorphic features. The genes responsible for the development of the phenotype have not yet been identified, but a distal localization is probable, since the cytogenetically visible and the cryptic deletions show a similar pattern of symptoms. We report a 33-year-old woman with a submicroscopic 22q13 deletion, mild mental retardation, speech delay, autistic symptoms and mild facial dysmorphic features. The deletion was mapped by FISH using cosmid probes from terminal 22q13, and the size of the deletion was estimated to be 100 kb. Three genes are affected by the deletion in this patient. ACR and RABL2B are deleted and proSAP2 is disrupted. This observation, together with recently published data, supports the notion that proSAP2 is the most important contributor to the 22q13 deletion phenotype.     

Deletion (X)(q26.1-->q28) in a proband and her mother: molecular characterization and phenotypic-karyotypic deductions.

During a routine prenatal diagnosis we detected a female fetus with an apparent terminal deletion of an X chromosome with a karyotype 46,X,del(X)(q25); the mother, who later underwent premature ovarian failure, had the same Xq deletion. To further delineate this familial X deletion and to determine whether the deletion was truly terminal or, rather, interstitial (retaining a portion of the terminal Xq28), we used a combination of fluorescence in situ hybridization (FISH) and Southern analyses. RFLP analyses and dosage estimation by densitometry were performed with a panel of nine probes (DXS3, DXS17, DXS11, DXS42, DXS86, DXS144E, DXS105, DXS304, and DXS52) that span the region Xq21 to subtelomeric Xq28. We detected a deletion involving the five probes spanning Xq26-Xq28. FISH with a cosmid probe (CLH 128) that defined Xq28 provided further evidence of a deletion in that region. Analysis with the X chromosome-specific cocktail probes spanning Xpter-qter showed hybridization signal all along the abnormal X, excluding the possibility of a cryptic translocation. However, sequential FISH with the X alpha-satellite probe DXZ1 and a probe for total human telomeres showed the presence of telomeres on both the normal and deleted X chromosomes. From the molecular and FISH analyses we interpret the deletion in this family as 46,X,del(X) (pter-->q26::qter). In light of previous phenotypic-karyotypic correlations, it can be deduced that this region contains a locus responsible for ovarian maintenance.     

Distal 11q monosomy syndrome: a report of two Egyptian sibs with normal parental karyotypes confirmed by molecular cytogenetics

Jacobsen syndrome is a rare disorder, caused by segmental monosomy for the distal end of the long arm of chromosome 11 with variable phenotypic expressivity. We report on the first male (6 years old) and female (3 years old) sibs with clinical and cytogenetics characterization of Jacobsen syndrome. Their karyotypes showed deletion 11q23.3-qter. Patients presented with growth and psychomotor retardation, facial dysmorphism, eye anomalies, and congenital heart disease (variable degrees of septal defect). Family history revealed a clinically similar brother, who died at 2 months old from cardiac anomalies in the form of single ventricle without being subjected to further investigations. Chromosomal analysis of the parents was normal. Karyotyping for the 2 patients and their parents was confirmed by fluorescence in situ hybridization analysis (FISH) using whole chromosome painting probes for 11 (WCP 11). Relevant investigations for both sibs showed mild thrombocytopenia with normal platelets morphology and striking periventricular demyelination on neuroimaging. Inguinal small testicles as well as focal epileptiform dysfunction were recorded in the male patient only. Abdominal ultrasound, hearing test, and DEXA scan were normal in both patients. Due to of the presence of apparently 3 affected offspring and normal parental karyotypes, an inherited predisposition was highly suspected. The large size of the distal deleted 11q segment in our patients support the recent hypothesis, that Jacobsen syndrome is a chromosomal deletion syndrome with genetic predisposition, due to expansion of p(CCG)n trinucleotide in the folate-sensitive fragile site FRA11B, at breakpoint 11q23.3. In conclusion, identification and further delineation of more similar patients will contribute to understanding the genetic basis of the 11q phenotype.     

A case with de novo interstitial deletion of chromosome 7q21.1-q22

A case with de novo interstitial deletion of chromosome 7q21.1-q22: A patient with multiple congenital anomalies was found to have a de novo proximal interstitial deletion of chromosome 7q21.1-q22. The patient was 10.5 years of age, and manifestations include growth retardation (below 3rd percentile), mental retardation, mild microcephaly, hypersensitivity to noise, mild spasticity, short palpebral fissures, alternant exotropia, compensated hypermetropic astigmatism, hypotelorism, hypoplastic labia majora and minora, clinodactyly of fingers 4 and 5. Molecular studies revealed that the deletion had a paternal origin, while chromosomes of both parents cytogenetically were shown to be normal. Molecular, and fluorescence in situ hybridization (FISH) analyses confirmed no deletion at the Williams-Beuren Syndrome region. Some of the heterogeneous clinical findings were consistent with previously reported cases of same chromosomal breakpoints.     

A girl with del(4)(q33) and occipital encephalocele: clinical description and molecular genetic characterization of a rare patient

We present clinical and developmental data on a girl with a de novo terminal deletion of the long arm of chromosome 4, del(4)(q33). The patient was evaluated at birth and followed up until 5 years of age. She showed facial and digital dysmorphism, a complex congenital heart defect, a large occipital encephalocele, and postnatal growth deficiency. Her neuropsychomotor milestones were delayed, and she developed learning difficulties. Apart from standard Giemsa banding, a molecular genetic analysis was performed using a comparative genomic hybridization (CGH) array. This revealed a terminal deletion at the band 4q32.3, which is directly adjacent to 4q33. The clinical findings in our patient differ from those described previously in patients with del(4)(q33) and del(4)(q32), respectively. In particular, the prominent occipital encephalocele has not been observed before in a terminal 4q deletion.     

Partial monosomy 11q and trisomy 12q: variable expression in two siblings

Clinical and cytogenetical findings are reported and discussed on two siblings with discordant phenotypes despite having both a terminal 11q deletion and a distal 12q duplication resulting from an unbalanced segregation of a balanced translocation t(11:12)(q23:q24.1) mat. The oldest child, a girl, is the index patient. Her clinical features include intrauterine and postnatal growth retardation, fetal distress, mild hypotonia, early feeding difficulties, moderate developmental delay, especially in language acquisition, a velopharyngeal insufficiency with repeated otorhinopharyngeal infections, facial dysmorphism, heart ventricular septal defect, and abnormal hyperactive behaviour with sometimes autistic tendencies. The facial dysmorphic features notably consist of microcephaly, hypertelorism, large palpebral fissures, large eyes with alternant divergent strabismus, long eyelashes, a long and broad nasal bridge, a short "crested" nose with salient tip, a fishmouth with large spaces between teeth and flat palate, retrognathism, large ears and multiple dimples. The second affected child is a boy showing low birthweight, moderate developmental retardation with mainly no active language at 32 months, behaviour abnormalities with an autistic tendency, and no major physical anomalies apart from a slight facial hypotonia with often open mouth, dimples on the shoulders and right cryptorchidism. The authors stress the variable clinical expression of the chromosomal imbalance in this family resulting in low birthweight, developmental delay, abnormal behaviour, but different degrees of physical features and dysmorphism. The possible contribution of each of the two aneusomies to the phenotype is discussed.     

Monosomy 10 qter

Summary An 11-year-old girl with 10q26qter deletion is described and compared with another patient reported in the literature. The most characteristic features of monosomy 10qter seem to be: severe mental retardation; growth retardation; microcephaly; and facial dysmorphism with a long and triangular facies, a broad and prominent nasal bridge, a poorly developed tip of the nose, a short philtrum, and flattened angles of the mandible. Several of these features are opposed in type and countertype to features of trisomy 10qter.Chargé de Recherche C.N.R.S.     

Combined deletion 18q22.2 and duplication/triplication 18q22.1 causes microcephaly,mental retardation and leukencephalopathy

Chromosome 18 abnormalities rank among the most common autosomal anomalies with 18q being the most frequently affected. A deletion of 18q has been attributed to microcephaly, mental retardation, short stature, facial dysmorphism, myelination disorders, limb and genitourinary malformations and congenital aural atresia. On the other hand, duplications of 18q have been associated with the phenotype of Edwards syndrome. Critical chromosomal regions for both phenotypes are contentious. In this report, we describe the first case of an 11-year old male with a combined interstitial duplication 18q22.1, triplication 18q22.1q22.2 and terminal deletion 18q22.2q23 with phenotypic features of isolated 18q deletion syndrome and absence of phenotypic features characteristic of Edwards syndrome despite duplication of the suggested critical region. This report allows for reevaluation of proposed critical intervals for the phenotypes in deletion 18q syndrome and Edwards syndrome.     

Pure partial trisomy 6p due to a familial insertion (16;6)(p12;p21.2p23)

There have only been eight patients with 6p pure trisomy involving different segments: four cases resulted from a translocation or insertion and four were due to an intrachromosomal duplication. We report here the first postnatally ascertained patient with a pure 6p partial trisomy due to an interchromosomal insertion (16;6)(p12;p21.2p23)mat. This rearrangement was confirmed by fluorescent in situ hybridization (FISH) with whole chromosome 6 and 16 painting probes. The clinical findings in the present patient were similar to those observed in previous cases, including craniofacial dysmorphism, minor anomalies, and lack of severe anatomical defects; yet, the unspecificity of many of these features prevented us from delineating the 6p pure trisomy syndrome.     

Report of a patient with a trisomy of chromosome region 20q11.2-->20q12 and characterization with FISH

We report on a 16-month-old boy presenting with psychomotor retardation, craniofacial anomalies and severe vision deficit. Analysis of GTG-banded chromosomes showed that the patient had extra chromosomal material in the long arm of one chromosome 20. This chromosome aberration was further characterized with FISH using a chromosome 20 specific paint and band-specific probes. A partial trisomy 20q was shown to be present, the karyotype being 46, XY, dup (20) (q11.2q12). The cytogenetic and clinical findings are compared with cases previously reported in the literature.     

Ring chromosome 10: report on two patients and review of the literature

Ring chromosome 10—r(10)—is a rare disorder, with 14 cases reported in the literature, but only two with breakpoint determination by high-resolution techniques. We report here on two patients presenting a ring chromosome 10, studied by G-banding, fluorescent in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA) and SNP-array techniques, in order to investigate ring instability and determine breakpoints. Patient 1 showed a r(10)(p15.3q26.2) with a 7.9 Mb deletion in 10q26.2-q26.2, while patient 2 showed a r(10)(p15.3q26.13) with a 1.0 Mb deletion in 10p15.3 and a 8.8 Mb deletion in 10q26.13-q26.3, both unstable. While patient 1 presented with clinical features usually found in patients with r(10) and terminal 10q deletion, patient 2 presented characteristics so far not described in other patients with r(10), such as Dandy-Walker variant, osteopenia, semi-flexed legs, and dermal pigmentation regions. Our data and the data from literature show that there are no specific clinical findings to define a r(10) syndrome.     

Subtelomeric chromosomal rearrangements detected in patients with idiopathic mental retardation and dysmorphic features

Subtelomeric chromosomal rearrangements detected in patients with idiopathic mental retardation and dysmorphic features: Cryptic aberrations involving the subtelomeric regions of chromosomes are thought to be responsible for idiopathic mental retardation (MR) and multiple congenital anomalies, although the exact incidence of these aberrations is still unclear. With the advent of chromosome-specific telomeric Fluorescence In Situ Hybridization (FISH) probes, it is now possible to identify submicroscopic rearrangements of distal ends of the chromosomes that can not be detected by conventional cytogenetic methods. In this study, cryptic subtelomeric chromosomal aberrations were detected in two of ten patients with idiopathic MR and dysmorphic features by using FISH probes of subtelomeric regions of all chromosome arms. A cryptic unbalanced de novo translocation was detected between the subtelomeric regions of the chromosome 10p and 18p in a patient with severe mental retardation, sensorineuronal deafness and several dysmorphic features. In the other patient, with mild mental retardation and dysmorphic features, a de novo subtelomeric deletion of chromosome 2q was found. In conclusion, in both familial and sporadic cases with idiopathic MR and dysmorphic features, the detection of chromosomal aberrations including subtelomeric rearrangements is of great importance in offering genetic counseling and prenatal diagnosis.     

A severely mental and motor retarded boy with monosomy 9pter-->p22 trisomy 10q26-->qter due to paternal reciprocal translocation 46,XY,t(9;10)(p23;q26)

We report on a twenty-two months old male patient with hypotonia, mental and motor retardation and trigonocephaly. Standard GTG banding chromosomal analysis (from metaphyses of a periferal blood lymphocyte culture) showed 46,XY, der(9) monosomy 9pter-->p22, trisomy 10q26--> qter karyotype. This unbalanced translocation resulted from the father's t(9,10) (p22;p26) karyotype. Deletions of the terminal part of 9p and partial trisomy of chromosome 10q are rare chromosomal disorders. To our knowledge, this is the first case report in the literature of a deletion of 9pter-->p22.3 and a duplication of 10q26-->qter. We assume that the clinical anomalies are due to der(9) monosomy 9pter-->p22, trisomy 10q-->26qter.