Biomedical subjects
Publications and source records attributed to K Devriendt.
We report two sibs with a similar syndrome of abnormal external ears, peculiar facial features, nail hypoplasia, a bilateral fibrous fusion of the outer third of the clavicle and the scapular spine, and the absence of a normal acromioclavicular joint. The present patients represent the fourth and fifth cases of the oto-onycho-peroneal syndrome (MIM 259780).
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Patients with a microdeletion on chromosome 22q11 demonstrate the clinical picture of the velocardiofacial syndrome. We report on three members of the same family with this microdeletion and velocardiofacial syndrome, all having an increase in platelet size and a mild decrease in platelet number. Their platelet function, however, tested by aggregation and by adherence to collagen in a whole blood perfusion system, was normal. We retrospectively studied the files of 35 other patients with 22q11 deletion and also found that their platelets had an increased size compared with cardiac controls. Moreover, their platelet size correlated negatively with platelet number. Knowing that patients with 22q11 deletion are obligate carriers for a heterozygous glycoprotein Ib beta deletion, these patients can be considered to be heterozygous Bernard-Soulier patients. In addition, a significant increase in platelet size may be a positive predictor for the clinical diagnosis of the velocardiofacial syndrome.
Prenatal diagnosis of the DiGeorge/velo-cardio-facial syndrome has become possible since it was recognized that this syndrome is caused by a submicroscopic deletion in chromosome 22q11. In a sporadic patient presenting a conotruncal heart defect and polyhydramnios, the del 22q11 was made prenatally by fluorescence in situ hybridization (FISH) after amniocentesis. Seven additional patients with a del 22q11 were identified, who presented during pregnancy with polyhydramnios. In one of them, unilateral hydronephrosis was present. These findings further add to a growing list of clinical presentations of a del 22q11 and suggest that in patients with polyhydramnios and a conotruncal heart defect or uropathy, fetal karyotyping should be complemented by FISH for a del 22q11.
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We report on a patient with neurosensory deafness, cataract and moderate mental retardation showing a constitutional mosaicism with the predominant cell line consisting of a 45,XY,-13,-15,+t(13;15) translocation of the Robertsonian type. By means of fluorescence in situ hybridization (FISH) using a panel of acrocentric pericentromeric probes and various banding techniques, the breakpoints in the translocation were determined at 13q12.1 and 15p13 respectively. Five other cell lines were present, at low percentage, one of them showing a t(13;15) tandem translocation. Interstitial telomeric sequences could be detected at the translocation fusion sites in both the Robertsonian and tandem translocations. The mosaicism appears therefore to be a consequence of chromosomal instability involving the t(13;15) fusion region of the predominant cell line, and related to the presence of interstitial telomeric sequences. The present observation suggests that in the pericentromeric 13q12 region, a gene involved in neurosensory deafness may be located.
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We present here a 6-year-old girl with the clinical signs of Wolf-Hirschhorn syndrome (WHS). Only after FISH studies the suspected 4p16.3 deletion could be confirmed. FISH studies in the mother showed that she was carrier of a balanced/unbalanced mosaicism with a 4p/16p translocation in 60% of the cells, and 4p16.3 deletion in 40% of the cells.
Further Delineation of the KBG syndrome: We present a mother and her daughter with clinical features of KBG syndrome, including mild mental retardation, distinct facial features, macrodontia and skeletal anomalies. In the daughter, a heart defect (ventricular septal defect) was present.
Localization by FISH of centric fission breakpoints in a de novo trisomy 9p patient with i(9p) and t(9q;11p): In this report we present a 38 year-old, severely mentally retarded female with 9p trisomy due to isochromosome 9p, i(9p), formation and translocation of the long arm of the rearranged chromosome 9 onto the telomere region of the short arm of chromosome 11: karyotype: 46, XX, -9, -11, +i(9p), +der(11) t(9;11) (q12;p15.5). C-banding showed that the i(9p) was monocentric and that der(11) had an additional C-band at the t(9q;11p) junction. The centric rearrangements were further identified by fluorescence in situ hybridisation (FISH) using a panel of chromosome 9 (peri)centric DNA probes. Analysis with probe pG-Xbal 1/340 (locus D4Z1), detecting the satellite subfamily at the centromeres of chromosomes 4 and 9, revealed small signals at the primary constriction of i(9p) but no signals at the breakpoint junction of the t(9q;11p). Further analysis using respectively chromosome 9 classical satellite probe (locus D9Z1), that consists of beta satellite sequences and pHuR98 probe (locus D9Z3) which detects satellite 3 DNA, localized to the 9qh region, both revealed translocation of these DNA sequences to the breakpoint of the t(9;11) junction. By using a 3'biotinylated oligonucleotide (TTAGGG)7 probe, no evidence was found for the presence of interstitial telomeric repeats at the t(9q;11p) breakpoint junction indicating that this derivative chromosome is the result of a reciprocal translocation with loss of telomeric regions including terminal 11p15.5-->pter. Our results provide evidence that the misdivision process that occurs on the chromosome 9 centric region results either from breakage in the alphoid DNA arrays or at the junction between alphoid and DNA regions.
We report on a dysmorphic and mentally retarded adult male patient with partial trisomy 1q resulting from a "de novo" tandem duplication of the 1q32.3-->q42 region. The dysmorphic features consisted of facial asymmetry, synophrys, right external strabismus, teeth anomalies and bilateral syndactyly of fingers III-IV and toes II-III evoking zygodactyly. Clinical comparison is made between the present observation and previously reported cases with pure duplication including the chromosome 1 segment (q32-->q42).
We present the clinical history and findings in 4 children and adolescents with the association of macrocephaly and cutis marmorata telangiectatica congenita (Macrocephaly-CMTC syndrome). This syndrome has recently been delineated within the general group of patients with manifestations of cutis marmorata telangiectatica-Klippel-Trenaunay-Weber syndrome as a clinically recognisable entity.
We present genotype-phenotype correlations in two patients with distal 10q deletion. A patient with a small terminal deletion presented mild mental retardation and behavioral difficulties with hyperactivity, whereas the patient with a larger deletion, had multiple congenital anomalies and moderate mental retardation. Our observation confirms the previous suggestion that larger deletions of distal chromosome 10q are associated with a more severe clinical presentation, whereas hyperactive behavior may be a specific feature of small terminal deletions of chromosome 10q26.
We present a patient with profound mental retardation, epilepsy, facial dysmorphism and multiple skin hyper- and depigmentation areas. Karyotype in white blood cells was normal female, whereas in cultured skin fibroblasts originating from a depigmentated area, mosaic 48,XX,+18,+20 was found. Molecular analyses using polymorphic microsatellites showed a different origin of both additional chromosomes: maternal for the chromosome 20, paternal for chromosome 18. This, together with a mosaic state is consistent with a double postzygotic error in chromosome segregation possibly occurring in a single cell division.