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E Haan

Publications and source records attributed to E Haan.

11 recordsLinked to original sources
PubMed1991

A de novo unbalanced reciprocal translocation identified as paternal in origin in the Prader-Willi syndrome.

Interstitial cytogenetic deletions involving the paternally derived chromosome 15q11-13 have been described in patients with the Prader-Willi syndrome (PWS). We report a child with PWS and a de novo unbalanced karyotype -45,XY,-9,-15,+der(9)t(9;15)(q34;q13). Molecular studies with the DNA probe pML34 confirmed that only a single Prader Willi critical region (PWCR:15q11.2-q12) copy was present. Hybridisation of patient and parental DNA with the multi-allelic probe CMW1, which maps to pter-15q13, showed that the chromosome involved in the translocation was paternal in origin. This is the first example of a paternally-derived PWCR allele loss caused by an unbalanced translocation that has arisen de novo.

Blotting, Southern↗
PubMed1991

Molecular and cytogenetic studies of the Prader-Willi syndrome.

Twenty-seven subjects with the Prader-Willi syndrome (PWS) were studied. Sixteen (59%) had a cytogenetic deletion involving chromosome 15q11-13. Nine were non-deletional and two patients had structural rearrangements of chromosome 15: 47,XY, + del(15)(pter----q12), var(15)(p11) and 45,XX,t(14q15q). At the DNA level, a greater proportion of patients (74%) showed loss of one chromosome 15q11-13 allele using a combination of densitometry and RFLP analysis. Deletion sizes were variable with 13 of 20 detectable both cytogenetically and with probe pML34 (D15S9). The remaining seven had microdeletions at the pML34 locus. Heterogeneity was further seen in three subjects who had cytogenetic deletions but normal DNA studies. In one patient there was evidence of a duplication at the pML34 locus. A new molecular rearrangement was identified with probe p3.21 (D15S10) in two patients and their mothers. Fifteen family studies were performed. In all 10 families where there was a molecular deletion, this was shown to have arisen de novo. DNA mapping confirmed that the paternal 15q allele was lost in three patients with PWS.

Adolescent↗
PubMed1991

Association of Treacher Collins syndrome and translocation 6p21.31/16p13.11: exclusion of the locus from these candidate regions.

Treacher Collins syndrome (TCS) is an autosomal dominant defect of craniofacial development which has not been chromosomally localized. We have identified a mother and two children who have TCS and also a balanced translocation t(6;16)(p21.31;p13.11), which suggested the possibility that the TCS locus might be located at one of the translocation breakpoints. These were defined by in-situ hybridization as 6p21.31 (by using loci in the HLA complex defined by the probes p45.1DP beta 003/HLA-DPB2 and pRS5.10/HLA class I chain) and 16p13.11 (by using probes pACHF1.3.2/D16S8 and VK45/D16S131). Pairwise and multipoint linkage analysis using localized chromosome 6 probes and chromosome 16 probes in 12 unrelated TCS families with multiple affected siblings excluded the TCS locus from proximity to both translocation breakpoints. These data were confirmed when a third affected child, who did not exhibit the translocation, was born to the mother.

Chromosome Banding↗
PubMed1988

A new method for the determination of L-dopa and 3-O-methyldopa in plasma and cerebrospinal fluid using gas chromatography and electron capture negative ion mass spectrometry.

L-3-(3,4-Dihydroxyphenyl)alanine (DOPA) and its 3-O-methyl metabolite (OMD) were measured in plasma and cerebrospinal fluid by a new assay which combines N,O-acetylation of amino acids in aqueous media, preparation of pentafluorobenzyl esters under anhydrous conditions, and analysis by gas chromatography-electron capture negative ion mass spectrometry. The N,O-acetyl, carboxy-PFB derivatives gave abundant carboxylate anions ([M-CH2C6F5]-) which were suitable for sensitive analysis using selected ion monitoring. Plasma and CSF samples were sufficiently purified by a simple organic solvent extraction. Analytical recovery for DOPA was 100.2 +/- 3.7% at the level of 100 nmol/l. Analysis of DOPA in plasma was performed with a relative standard deviation of 5%. The limit of quantitation in plasma and CSF was at the sub-nmol/l level. In healthy adults, DOPA concentration in plasma was 9.0 +/- 2 nmol/l (n = 11) and in CSF 3.5 +/- 0.9 nmol/l (n = 9). The concentration of OMD in plasma was 99.1 nmol/l (pool of 24 samples) and 15.3 nmol/l in CSF (pool of 12 samples). Measurement of 5-[2H]DOPA and 5-[2H]OMD in plasma of a healthy individual who had been orally loaded with 3,5-[2H2]tyrosine (150 mg kg body wt) was possible for several hours after the load.

Acetylation↗
PubMed1988

The gene for incontinentia pigmenti: failure of linkage studies using DNA probes to confirm cytogenetic localization.

Probes for restriction fragment length polymorphisms mapping between Xp21 and Xq22.3 have been used in a linkage study of incontinentia pigmenti (IP). Six independent sporadic cases of disorders resembling IP with X-autosome translocations involving the same X chromosome breakpoint (Xp11) have been reported. These observations suggest that the IP gene may be located in the Xp11 chromosomal region. However, the linkage study with DNA probes has failed to confirm this localisation.

Chromosome Mapping↗
PubMed1987

Nonketotic hyperglycinemia: analyses of glycine cleavage system in typical and atypical cases.

The molecular nature of the glycine cleavage system was investigated in eight patients with typical (neonatal) and two patients with atypical (late onset) nonketotic hyperglycinemia (NKH). The overall activity of the glycine cleavage system was found to be decreased in all of the liver and brain tissue studied, but it was undetectable or extremely low in typical NKH, whereas there was some residual activity in atypical NKH. Six patients with typical NKH had a specific defect in the P protein, and one a defect in the T protein; the activity of the T protein was defective in one patient with atypical NKH.

Amino Acid Oxidoreductases↗
PubMed1986

Leigh's disease.

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Brain Diseases, Metabolic↗
PubMed1985

Severe illness caused by the products of bacterial metabolism in a child with a short gut.

An 8-year-old boy with a short gut had six episodes of metabolic acidosis and neurological dysfunction over a 1 month period. The neurological features consisted of a depressed conscious state, confusion, aggressive behaviour, slurred speech and ataxia. The organic acid profile of urine demonstrated increased amounts of lactic, 3-hydroxypropionic, 3-hydroxyisobutyric, 2-hydroxyisocaproic, phenyllactic, 4-hydroxyphenylacetic and 4-hydroxyphenyllactic acids. Of the lactic acid 99% was D-lactic acid. The anaerobic gut flora consisted almost entirely of Lactobacilli in unusually large numbers. A course of vancomycin prevented further episodes. A urinary organic acid profile may be diagnostic when a person with a short gut develops metabolic acidosis or an unusual encephalopathy and bacterial metabolites should be considered in other patients with unusual combinations of organic acids in the urine.

Acidosis↗
PubMed1979

The identification of 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid in a patient with propionic acidemia.

Two abnormal metabolites, 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, have been identified and quantitated in the urine of a child with propionic acidemia. These metabolites may be produced as a result of the self-condensation of propionyl-CoA. Data are presented to show that the unusual ketone, 3-pentanone, which has been observed previously in the urine of patients with propionic acidemia, is produced as a result of the decarboxylation of 3-keto-2-methylvaleric acid.

Gas Chromatography-Mass Spectrometry↗