Usefulness of icterometer in black newborns with jaundice.
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Bilirubin↗
Biomedical subjects
B C Hamel
Publications and source records attributed to B C Hamel.
The Beckwith-Wiedemann syndrome in four African infants.
Four cases of Beckwith-Wiedemann syndrome are reported. The clinical, pathological, radiological and laboratory findings in the syndrome are reviewed. The risk of intraabdominal malignancy in both the complete and incomplete forms is stressed and the consequent importance of early diagnosis emphasised. Early recognition of hypoglycaemia in infants with an omphalocele is also advocated. It is considered that the findings in one case indicate possible hyperresponsiveness of insulin secretion to i.v. glucose. The incidence of the syndrome is estimated to be 1/15000 births.
Beckwith-Wiedemann Syndrome↗
Case report - lethal neonatal chickenpox.
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Chickenpox↗
Oculocutaneous albinism associated with motor neuron disease.
The patient described is a 14-year-old girl who suffered from an oculocutaneous albinism. The developmental milestones were reached with some delay. Gradually she experienced fatiques, and wasting of the pelvic girdle muscles and weakness appeared. In suralis nerve biopsy sections no abnormalities were found. In muscle biopsy sections the characteristic findings of a primary central neuronal muscular atrophy were seen. Based on clinical and histopathological findings it may be stated that the patient is suffering from a motor neuron disease. The chance of the combined occurrence of oculocutaneous albinism and motor neuron disease can be estimated to be one out of 750 X 10(6), unless an incestuous relation is supposed.
Adolescent↗
Penetrance of fra(X) gene: influence of grandparental origin of the gene, mental status of the carrier mother, and presence of a normal transmitting male.
Previous studies have indicated that the fragile X [fra(X)] gene does not show full penetrance (mental impairment) in carrier females or "carrier" males. The phenomenon of non-expressing carrier males distinguishes the fra(X) syndrome from all other known X-linked disorders. Moreover, penetrance of the fra(X) gene apparently does not show random distribution within fra(X) families, but seems to be reduced in sibs of normal transmitting males (NTM's). The availability of many large multigeneration fra(X) families, studied by cytogenetic and DNA analyses, enabled us to refine the estimates of the penetrance. From our data we conclude that the penetrance in daughters of carrier females is determined by the mental status of the mother. In sons of carrier females, the observed penetrance appears to be influenced by the grandparental origin of the gene as well as by the mental status of the mother. However, in contrast with the average penetrance, we observed a strongly reduced penetrance of the fra(X) gene in brothers (14%) and sisters (21%) of NTM's. These findings have profound implications for genetic counseling.
Cytogenetics↗
The gene for X-linked myotubular myopathy is located in an 8 Mb region at the border of Xq27.3 and Xq28.
X-linked recessive myotubular myopathy (XLMTM) is a rare and severe neonatal neuromuscular disease characterized by muscle weakness, hypotonia, and respiratory problems. Here we report an extensive linkage analysis in two families with XLMTM. Using 18 markers in the Xq27-Xqter region we found a maximum two-point lod score of Z = 4.00 at theta = 0.00 for the marker II-10 (DXS466). Three recombinations were detected between markers and the disease locus. At the distal side of Xq27.3 a recombination was present in between RNI (DXS369) and VK23b (DXS297), another in between VK23b (DXS297) and II-10 (DXS466), and at the proximal side of Xq28 a recombination in between U6.2 (DXS304) and Cpx67 (DXS134). Combining the results of both families we conclude that XLMTM is located in the 8 Mb(11 cM) region between VK23b (DXS297) and Cpx67 (DXS134).
Adult↗
The clinical phenotype in institutionalised adult males with X-linked mental retardation (XLMR).
In an institutionalised population of 471 mentally retarded adult residents (436 males and 35 females), 22 males (i.e. 5 % of the male population) had XLMR, accounting for 36.1 % of the residents diagnosed with a monogenic disorder (n = 61). Fragile X syndrome (FRAXA) was diagnosed in 16 residents, X-linked mental retardation with marfanoid habitus (Lujan-Fryns syndrome) in 2, and non-specific X-linked mental retardation (MRX) in 4 males. The 4 MRX-patients included 3 male sibs of a family, carrying a mutation in the IL-1 receptor accessory protein-like gene, and one male patient member of the MRX-44 family (linkage with LOD-score of 2.90). In the group of 215 males with idiopathic mental retardation (MR), family histories and pedigree data were compatible with XLMR in 35 males (35/215 = 16.3 %) from 32 families. Of these 35 males, 5.7 % were microcephalic with dysmorphic features and 5.7 % macrocephalic; micro-orchidism and macro-orchidism were each found in 11.4 %. One macrocephalic male had also macro-orchidism and dysmorphic features. In this study, the diagnosis of XLMR could thus be proposed in 57 males i.e. 13.1 % of the total male population. The clinical phenotype, behavioural problems and follow-up data in these different subgroups of XLMR are presented.
Adult↗
Evidence against a major role of PEG1/MEST in Silver-Russell syndrome.
Silver-Russell syndrome (SRS) is a heterogeneous disorder characterised by interauterine and postnatal growth retardation, with or without additional dysmorphic features. Most cases are sporadic but a few familial cases have been described. A subset of patients exhibit maternal uniparental disomy for chromosome 7 (mUPD7) strongly suggesting that genomic imprinting plays a role in the aetiology of the disease. We and others have recently characterised the human PEG1/MEST gene, the first imprinted gene known to be located on chromosome 7. Although the function of PEG1/MEST is unknown, the paternal-specific expression of this gene and its location at 7q32, render it a promising candidate for SRS. As a prerequisite for mutation screening in 49 patients with SRS and 9 with primordial growth retardation (PGR), we determined the complete genomic structure of the PEG1/MEST gene which consists of 12 exons. Apart from one silent mutation and two novel polymorphisms, nucleotide changes were not detected in any of these patients. Moreover, methylation patterns of the 5' region of PEG1/MEST were found to be normal in 35 SRS and 9 PGR patients and different from the pattern seen in patients with mUPD7. These findings strongly argue against a role of PEG1/MEST in the majority of Silver-Russell syndrome cases.
Abnormalities, Multiple↗