Biomedical subjects
Publications and source records attributed to J J Engelen.
In the group of patients with terminal 11q deletion reported up to now. Jacobson syndrome has been delineated as a distinct clinical entity. In the present report we describe the clinical findings in a 3-year old girl with de novo deletion 11q24.2-->11qter, and compare the findings with Jacobson syndrome.
We present a 6-year-old boy with moderate developmental delay, gait disturbance, autism related disorder and mild dysmorphic features. He was seen for evaluation of his retardation since the age of 2.8 years. At first sight, a cytogenetic analysis showed a normal 46,XY karyotype. Neurological examination at the age of 5.5 years revealed a motor and sensory polyneuropathy. A quantitative Southern blot with probes PMP22 and VAW409 specific for Charcot-Marie-Tooth type 1 (CMT1) disclosed a duplication which confirmed the diagnosis HMSN Ia. Subsequently, GTG banded metaphases were re-evaluated and a small duplication 17p was seen on retrospect. Additional FISH with probe LSISMS (Vysis) specific for the Smith-Magenis region at 17p11.2 again showed a duplication. Both parents had a normal karyotype and the duplication test for CMT1 showed normal results for both of them. The boy had a de novo 46,XY,dup(17)(p11.2p12) karyotype. The present observation confirms previous findings of mild psychomotor delay, neurobehavioural features and minor craniofacial anomalies as the major phenotypic features of dup(17)(p11.2) and dup(17)(p11.2p12); in cases of duplications comprising the PMP22 locus HMSN1 is associated. A recognizable facial phenotype emerges characterized by a broad forehead, hypertelorism, downslant of palpebral fissures, smooth philtrum, thin upper lip and ear anomalies.
We report on a 2-year-old boy presenting with growth and psychomotor retardation and facial anomalies, including a flat face with prominent forehead, a flat nasal bridge and flat occiput, unusually long curved eyelashes, and a thin upper lip with down-turned corners of the mouth. Analysis of GTG-banded chromosomes demonstrated that the patient had extra chromosomal material in the long arm of one chromosome 5. This chromosome aberration was characterized further using microdissection and FISH with band-specific probes and a de novo direct duplication (5)(q31.3q33.3) was shown to be present. We have compared this case with others known to be partially trisomic for chromosome 5q reported in the literature.
We report on a newborn boy with a congenital heart defect, severe pre- and postnatal growth retardation, feeding problems, facial anomalies and unilateral hydronephrosis. Cytogenetic analysis showed extra chromosomal material on the short arm of one chromosome 15 that at first sight could be mistaken for a chromosomal variant and could not be identified with conventional banding techniques. Chromosome analysis of the parents showed that both had a normal karyotype. Microdissection of five copies of the aberrant chromosome 15, amplification of the dissected chromosomal material by DOP-PCR and subsequent reverse painting was performed and disclosed that the patient had a de novo 46,XY,der(15)(6pter-->6p22.1::15p12-->15qter) karyotype with a "pure" trisomy of chromosome region 6p22.1-->6pter. The associated phenotypic anomalies are compared with other reported cases with a distal duplication of chromosome 6p.
A female new-born with bilateral lateral facial clefts, resulting in macrostomia, is reported. In addition she had a diminished palpebral fissure length. She died suddenly at the age of 6 months, presumably due to respiratory insufficiency. The unique combination of facial anomalies, present in this patient, has not been reported before. We discuss the differential diagnosis and the classification of facial clefts.
We present a male infant with preauricular skin tags and pits, downslanting palpebral fissures, hypertelorism, ectopic anus, hypospadias, and hypoplastic left heart syndrome. The clinical features in our patient show phenotypic overlap with the cat eye syndrome, as illustrated by the review of 105 reported cases. Cytogenetic analysis revealed a supernumerary marker chromosome, which was identified by microdissection and fluorescence in situ hybridization as an isodicentric chromosome 22(pter --> q11.2::q11.2 --> pter). It was proved with probes specific for the cat eye syndrome critical region that this region was present in quadruplicate in the propositus. We conclude that CES is characterized by large phenotypic variability, ranging from near normal to severe malformations, as reflected in the neurodevelopmental outcome. Preauricular skin tags and/or pits are the most consistent features, and suggest the presence of a supernumerary bisatellited marker chromosome 22 derived from duplication of the CES critical region.
Holoprosencephaly (HPE) is a developmental field defect with impaired cleavage of the embryonic forebrain as the cardinal feature. The prevalence is about 1 in 11.000-20.000 in live births and 1 in 250 during embryogenesis. In most cases, craniofacial abnormalities are associated and reflect in 80% of cases the degree of severity. The severity is of marked variability and ranges from cyclopia to minimal craniofacial dysmorphism, such as mild microcephaly with a single central incisor. The etiology of HPE is very heterogeneous and comprises environmental factors (e.g. maternal diabetes) and genetic causes. Approximately 50% of HPE cases are associated with a cytogenetic abnormality (the most common of which is trisomy 13) or a monogenic syndrome. Based on recurrent cytogenetic abnormalities, there are at least 12 genetic loci that likely contain genes implicated in the pathogenesis of HPE. Currently, four human HPE genes are known: SHH at 7q36, ZIC2 at 13q32, SIX3 at 2p21 and TGIF at 18p11.3. Over the past 13 years, 16 patients with HPE have been observed at the Department of Clinical Genetics at Maastricht. Some of them are briefly presented in order to emphasize the spectral nature of HPE and the etiological heterogeneity. One patient appeared to have a partial 18p deletion due to a maternal cryptic translocation t(1:18) and, in addition, a SHH mutation. The mildest affected patient presented with microcephaly and a single maxillary incisor; she had a submicroscopic 7q deletion. Finally, we propose a protocol of etiological work-up of HPE cases.
We describe a family with direct transmission of a duplication of 8p12-->8p21.1. The phenotype of affected relatives included mild mental retardation but no minor anomalies. The duplication was identified by means of GTG-banding and fluorescence in situ hybridization with a probe specific for 8p12 generated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction. Assay of glutathione reductase, which has been localised to 8p21.1, was significantly increased when compared with controls with normal chromosomal constitution. To the best of our knowledge, a proximal direct duplication of 8p restricted to subbands p12-->p21.1 has not been reported so far. The reported aberration is compared with other partial duplications of 8p, in particular to inversion duplications 8p and to small direct distal duplications involving 8p23.1. Am. J. Med. Genet. 94:306-310, 2000.
Mental retardation and congenital malformations in individuals with small ring X chromosomes are often due to the functional disomy that results from failure of these chromosomes to undergo X inactivation. Such chromosomes either lack the XIST locus or do not express it. We have carried out genetic analysis of the ring X chromosomes from two girls with a 45,X/46,X,r(X) karyotype, mental retardation, and a constellation of abnormalities characteristic of the severe phenotype due to X disomy. In each case the ring X chromosome included an intact XIST locus which was expressed; the breakpoints were distal to DXS128, and therefore outside the XIC region; transcription analysis of alleles at the androgen receptor locus confirmed that these were inactive chromosomes. The characteristics of the XIST RNA were similar to the wild-type. Additional studies in cultured fibroblasts showed a second ring in a small percentage of the cells. The association of severe phenotype with an inactive X chromosome most likely reflects the presence of a second ring X chromosome which was active at least in some tissues during embryogenesis, but is no longer prominent in the tissues we analyzed.
In a 6-year-old girl referred because of mild motor delay and hyperextensible joints, chromosome analysis disclosed a derivative chromosome consisting of end-to-end fusion of chromosomes 2 and 14. Two cell lines existed in which this telomere association was present, one with a 45,XX,tas(2;14)(q37;p11) karyotype and one with a 45,XX,tas(2;14) (q37;q32) karyotype. The cell line with the telomeric fusion of 2q and 14p was present in 90% of the cells; a telomeric fusion of 2q and 14q was seen in the remaining 10% of the cells. In both association complexes, only the centromere of chromosome 14 was active. Fluorescence in situ hybridization with telomere and subtelomere probes disclosed no deletion of chromosomal material. Microsatellite analysis showed that the patient had a normal biparental contribution of chromosomes 14.
Chromosome analysis was performed in a 34-year-old man who was phenotypically normal except for oligoasthenozoospermia. In this patient, analysis of GTG-banded chromosomes showed in one chromosome 8 additional chromosomal material of unknown origin. To characterize the aberrant chromosome more precisely, a paint specific for chromosome region 8pter-->8p23.1 was generated by microdissection and degenerated oligonucleotide primed-polymerase chain reaction (DOP-PCR) and used as fluorescence in situ hybridization (FISH) paint. After reverse painting, hybridization signals were only found on the short arm of the two chromosomes 8, with an enlarged signal on the derivative chromosome 8. The duplication was characterized further with band-specific FISH probes. We concluded that (part of) chromosome region 8p23.1-->p23.3 was duplicated. Chromosome analysis of the parents showed that the dup(8) was of maternal origin and that the fertile brother of the index patient also was a carrier of the chromosome aberration. There was no history of miscarriages. We suggest that duplication of region 8p23.1-->p23.3 can be regarded as euchromatic variant or duplication with no phenotypic effect.
MicroFISH was used to elucidate the chromosomal origin of a prenatally detected marker chromosome. Five copies of the marker chromosome were collected from GTG-banded metaphases and amplified by means of DOP-PCR. The PCR product was labeled with blotine-14-dATP and used as a FISH probe for hybridization to metaphase chromosomes of the fetus (reverse painting). The marker appeared to be derived from the short arm of (an) acrocentric chromosome(s). After FISH with centromere-specific and band-specific probes complete characterization was possible and the marker chromosome appeared to consist of two short arms of chromosome 22. The pregnancy was continued and one year after birth the patient is developing normal.
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.
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.
A fetal patient presented at 27.3 weeks of gestation with polyhydramnion. Ultrasound examination showed enlarged cerebral ventricles, abnormal position of the fingers and abnormal external genitals. Chromosome studies in chorionic villus material were normal male: in cultured amniocytes a distal deletion 14q32 was demonstrated and confirmed by FISH analysis. The baby was born at 37 weeks and died spontaneously during labour. This is the first report of prenatal diagnosis of a terminal 14q deletion.
Two patients with a trisomy 7p are reported. Both were assessed by facial dysmorphism and congenital anomalies. In one of the patients trisomy 7p was a de novo event, in the other patient unbalanced inheritance of a parental translocation caused trisomy 7p. Developmental delay was severe in both. Our 2 cases are compared with patients reported in literature.
Various markers of radiation-induced DNA damage including DNA oxidation were investigated in peripheral lymphocytes of 23 cancer patients prior to and one week after receiving radiotherapy with a cumulative dose of 54-70 Gy. Exposure to ionizing radiation nonsignificantly increased the ratio 2'deoxy-7-dihydro-8-oxoguanosine/2'deoxyguanosine (8-oxodG/dG) from 1.73 x 10(-5) to 3.33 x 10(-5). Frequencies of micronuclei significantly (p = 0.0003) increased from 6.4 to 38.9 per 1000 cells. The frequency of hypoxanthine-guanine-phosphoribosyltransferase (HPRT) mutant lymphocytes measured as 6-thioguanine resistant variant cells by 5-bromodeoxyuridine labeling, was elevated eight-fold, from 4.7 x 10(-6) to 36.2 x 10(-6) (p = 0.008) after termination of the radiotherapy, thus showing a clear response to the radiation treatment. No correlation between levels of oxidative DNA damage and frequencies of HPRT mutant lymphocytes or micronuclei could be established.
Cryptic unbalanced chromosome rearrangements in the telomeric bands of the chromosomes may constitute a significant cause of unexplained mental retardation with or without congenital anomalies. We report on a boy with a terminal deletion of the long arm of chromosome 13, combined with a partial duplication of the short arm of chromosome 20, owing to a cryptic balanced translocation in his father. The karyotype of the father was 46XY,t(13;20)(q34;p13). The propositus presented with severe mental and growth retardation, microcephaly, facial anomalies including ptosis of the right upper eyelid, a high nasal bridge, small palpebral fissures, and bilateral epicanthus, hypospadias, and scoliosis. A younger brother died at birth and had a low birth weight, hypospadias, and a horseshoe kidney. Repeated chromosome analyses with high resolution banding in the propositus and his parents were apparently normal. Chromosome painting eventually disclosed the cryptic translocation in the father with unbalanced karyotype in the propositus. The importance of additional FISH analysis in patients with unexplained mental retardation, physical anomalies, and apparently normal chromosomes is emphasized.