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Ron Hochstenbach

Publications and source records attributed to Ron Hochstenbach.

6 recordsLinked to original sources
PubMed2006

A familial inverted duplication 2q33-q34 identified and delineated by multiple cytogenetic techniques.

We describe a unique family with two children having a delay in psychomotor development. In both children we identified an interstitial duplication dup(2)(q34q33) using multiple, complementary molecular cytogenetic techniques. Comparative genomic hybridisation (CGH) and array-CGH were used to determine the size and the location of the duplicated region, the orientation of the duplicated region was identified with fluorescence in situ hybridisation (FISH). Both parents demonstrated a normal karyotype and normal CGH and array-CGH-profiles. However, FISH on peripheral blood cells from the mother showed the inv dup(2) in 9% of metaphases and 19% of interphase nuclei. To our knowledge this is the first report of a mosaic carrier of duplication in the long arm of chromosome 2. The finding of chromosomal mosaicism of at least 19% in the mother increases the recurrence risk. The exact characterisation of the inv dup(2) with FISH probes enabled us to offer a reliable prenatal FISH test. Comparison of the clinical features of the two children with those of previously described cases supports the hypothesis that the characteristic facial phenotype is linked to the distal part of the 2q33-q37 region. This report illustrates that in case of two sibs with an identical structural chromosomal abnormality the possibility of parental chromosomal mosaicism must be thoroughly investigated.

Chorionic Villi Sampling↗
PubMed2005

Selective chromosome analysis in couples with two or more miscarriages: case-control study.

OBJECTIVE: To identify additional factors, such as maternal age or factors related to previous reproductive outcome or family history, and the corresponding probability of carrying a chromosome abnormality in couples with two or more miscarriages. DESIGN: Nested case-control study. SETTING: Six centres for clinical genetics in the Netherlands. PARTICIPANTS: Couples referred for chromosome analysis after two or more miscarriages in 1992-2000; 279 carrier couples were marked as cases, and 428 non-carrier couples served as controls. MAIN OUTCOME MEASURES: Independent factors influencing the probability of carrier status and the corresponding probability of carrier status. RESULTS: Four factors influencing the probability of carrier status could be identified: maternal age at second miscarriage, a history of three or more miscarriages, a history of two or more miscarriages in a brother or sister of either partner, and a history of two or more miscarriages in the parents of either partner. The calculated probability of carrier status in couples referred for chromosome analysis after two or more miscarriages varied between 0.5% and 10.2%. CONCLUSIONS: The probability of carrier status in couples with two or more miscarriages is modified by additional factors. Selective chromosome analysis would result in a more appropriate referral policy, could decrease the annual number of chromosome analyses, and could therefore lower the costs.

Abortion, Spontaneous↗
PubMed2004

Cerebellar hypoplasia, zonular cataract, and peripheral neuropathy in trisomy 17 mosaicism.

Trisomy 17 mosaicism in liveborns is an extremely rare chromosomal abnormality, with only three cases reported in the literature. Here we describe a 7-year-old boy with trisomy 17 mosaicism. The chromosome abnormality was detected by amniocentesis and was confirmed postnatally in cultured skin fibroblasts. The main clinical features were mental retardation and growth reduction, peripheral motor and sensory neuropathy, hypoplastic cerebellar vermis, zonular cataract, and body asymmetry. In our patient, and in the three earlier described cases, the additional chromosome 17 was detected in skin fibroblasts, not in peripheral lymphocytes. Molecular investigations excluded uniparental disomy of chromosome 17 in our patient. The extra chromosome 17 probably originated from a postzygotic mitotic nondisjunction of the maternal chromosome 17. In most cases of trisomy 17 mosaicism detected in amniocytes the chromosome abnormality seems to be confined to extra-embryonic tissues and clinically normal children are born. If, however, there are also ultrasound abnormalities, the possibility of fetal trisomy 17 mosaicism should certainly be considered. If postnatal karyotyping is limited to blood the diagnosis of trisomy 17 mosaicism could easily be missed. Therefore, we recommend chromosome analysis to be based on cultured skin fibroblasts in all cases where mental retardation is accompanied by postnatal growth retardation, body asymmetry, peripheral neuropathy, and cerebellar hypoplasia or zonular cataract.

Cataract↗
PubMed2004

Mosaic trisomy 22 in a boy with a terminal transverse limb reduction defect.

A terminal transverse limb reduction defect is a relatively common congenital malformation that most often occurs unilaterally and in isolation. A mildly mentally disabled boy is described with an absent left hand, a congenital cardiac defect, short stature, facial dysmorphism and skin pigmentary anomalies. Karyotyping of fibroblasts revealed mosaic trisomy 22. Most of the clinical features of our patient are consistent with the phenotype of mosaic trisomy 22, however, a terminal transverse reduction defect has until now never been reported in association with this chromosomal aberration.

Child↗
PubMed2002

Two cases with partial trisomy 9p: molecular cytogenetic characterization and clinical follow-up.

This paper describes two patients with partial trisomy 9p and partial trisomy 14q due to 3:1 segregation from de novo maternal reciprocal translocations. The breakpoints are different from previously described 9;14 translocations and their 3:1 segregation products. The clinical phenotype of both cases is compatible with the partial trisomy 9p syndrome. We present the follow-up of both patients from birth up to age 7 years. Partial trisomy 9p is a frequently described chromosome abnormality. This does not appear to be related to a breakage sensitive locus on chromosome 9p, since the trisomic fragments of the published cases are heterogeneous. In the two cases described here, GTG-banded karyotyping suggested that the 9p breakpoints were similar; DNA marker analysis, however, showed them to be different. Such DNA studies will be necessary to define the genotype-phenotype relation in partial trisomy 9p syndrome.

Child↗