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Biomedical subjects

B C Hamel

Publications and source records attributed to B C Hamel.

At least 109 records · Page 6Linked to original sources
PubMed1992

Sex ratios of affected and transmitting members of multiple case families with neural tube defects.

In order to study the genetic aspects of the relation between neural tube defects and sex, we selected families with at least two closely related affected members. The sex ratios of both affected and normal transmitting persons were determined in these multiple case families. Our results indicate that there is a relation between the position of the lesion in the spine and sex. Furthermore, the affected persons in one family show significant concordance for sex as shown by the analysis of families with just two affected members. To our surprise, the group of normal transmitters appears to consist of significantly more females than males. This is in contrast to similar families with non-syndromic cleft lip +/- palate, where males predominate both among affected persons and normal transmitters. Finally, affected females most often inherited the predisposition to a neural tube defect from their mother. The possible role of inherited factors is discussed.

Female↗
PubMed1992

Intestinal pseudo-obstruction in myotonic dystrophy.

We describe four myotonic dystrophy (DM) patients who developed recurrent intestinal pseudo-obstruction. Some episodes were associated with gastroenteritis, while abdominal crowding may have occurred in one case during the third trimester of pregnancy. In most instances, however, no apparent cause could be identified. Intestinal pseudo-obstruction may occur at any stage of DM. In one of our cases intestinal pseudo-obstruction preceded significant muscle weakness by 15 years. Intestinal pseudo-obstruction is usually treated effectively with conservative measures. These include restriction of oral intake, intravenous fluids, and multiple enemas or colonoscopy. Improved intestinal function was noted in one case treated with the prokinetic agent cisapride. A partial sigmoid resection was performed in three cases with dolichomegacolon. No abnormalities were reported on histological examination. Since intestinal pseudo-obstruction is a rare complication of DM, it is of interest that two of our cases are sibs. Review of published reports showed several reports of familial occurrence of specific complications. These include cardiac conduction disturbances, focal myocarditis, mitral valve prolapse, pilomatrixomas, polyneuropathy, normal pressure hydrocephalus, and dilatation of the urinary tract. Myotonic dystrophy may show a tendency to familial clustering of organ specific involvement.

Adult↗
PubMed1992

Restrictive dermopathy in two brothers.

BACKGROUND: Restrictive dermopathy is an autosomal recessive phenotype characterized by universal tautness of skin resulting in fetal akinesia and death during the neonatal period. The clinical signs and symptoms of this uncommon disease are described in two brothers, and evidence is provided that fetal biopsy specimens obtained during the 20th week of gestational age are nondiagnostic. OBSERVATIONS: The first patient was a growth-retarded preterm boy suffering from generalized desquamation, marked joint contractures, and facial hypoplasia. Prominent light microscopic findings were hyperorthokeratosis intermingled with parakeratosis and absence of the elastic fibers in a thinned dermis. Electron microscopic examination of the epidermis revealed a lack of keratin filaments and an abnormal globular shape of the keratohyalin granules. The child died 4 days after birth. A following pregnancy resulted in birth of a preterm boy who died of the same disease within 2 hours. In the 20th week of gestational age, fetal biopsy specimens were obtained, but light and electron microscopy failed to reveal any abnormalities. CONCLUSIONS: Restrictive dermopathy is a genuine skin disease resulting in fetal akinesia that precludes a normal intrauterine development. The clinical features of this disorder are so distinctive that an on-the-spot diagnosis can be established. In view of the data obtained in this case, the feasibility of prenatal diagnosis should be regarded with great caution.

Face↗
PubMed1991

Myotonic dystrophy. Predictive value of normal results on clinical examination.

Myotonic dystrophy (DM) is well known for its highly variable clinical picture, including the age at which symptoms are first detected. In order to assess the proportion of asymptomatic gene carriers at different ages, we have used linked DNA markers to study individuals at 50% genetic risk of DM, in whom neurological examination, slit-lamp examination and electromyography (EMG) had failed to show diagnostic signs. A total of 139 asymptomatic offspring of DM patients were studied. Our analyses identified 11 out of these 139 as probable gene carriers. Our data show that penetrance of the DM gene increases with age. After correction for the possibility of genetic recombination between the DM gene and the DNA markers used, we calculated the residual chance of carrying the DM gene as 8.3% for clinically normal offspring aged between 20 and 39 yrs. We evaluated several factors that might influence this figure. Neither the sex of the propositus nor that of the affected parent modified the risk of carrying the DM gene. Presence of aspecific lens opacities also did not correlate with the risk of having inherited the DM gene. Since a significant proportion of DM gene carriers are not detected by neurological examination, including slit-lamp examination and EMG, these results confirm the need for DNA analysis in asymptomatic offspring of DM patients.

Biomarkers↗
PubMed1990

[Polydactyly].

Explore the source record for details and available documents.

Congenital Abnormalities↗
PubMed1990

Acrocallosal syndrome.

Acrocallosal syndrome is an autosomal recessive disorder of brain malformation and complex polydactyly. We report on an additional patient with this disorder. It is suggested that increased birth weight and cerebellar hypoplasia occur in acrocallosal syndrome. The finding of an extra bone within the anterior fontanel in our patient suggests similarity to the Xt mouse mutant, which is homologous to Greig syndrome in man. This provides additional support for the hypothesis of allelism of the Greig and acrocallosal syndromes.

Animals↗
PubMed1989

Autosomal recessive intestinal lymphangiectasia and lymphedema, with facial anomalies and mental retardation.

We report on two male and two female relatives with intestinal lymphangiectasia; severe lymphedema of limbs, genitalia, and face; facial anomalies; seizures; mild growth retardation; and moderate mental retardation. Main facial anomalies are a flat face, flat nasal bridge, hypertelorism, small mouth, tooth anomalies, and ear defects. Their parents are consanguineous. This disorder probably is an hitherto undescribed autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1988

Myoadenylate deaminase deficiency: a clinical, genetic, and biochemical study in nine families.

The clinical significance of myoadenylate deaminase (MAD) deficiency and its mode of inheritance is still questioned. There were 36 relatives of 9 unrelated MAD deficient patients who were examined with the aid of a standardized ischemic forearm test: 8 new cases of MAD deficiency were detected, 5 of which were confirmed histochemically and biochemically. Obligate heterozygotes showed a normal ammonia production and MAD staining, but the mean activity of the enzyme was significantly less than in a group of controls. The results obtained from the family study strongly suggest an autosomal recessive mode of inheritance. However, only 2 of the 8 newly found MAD deficient individuals complained of exertional myalgia, whereas the remaining 6 were without any symptoms or complaints. This finding casts doubt on the clinical significance of MAD deficiency and the relationship of the deficiency state with exertional myalgia.

AMP Deaminase↗
PubMed1988

A family with complex bilateral polysyndacty.

A six-generation family with 88 members is described. A curious combination of polydactyly, syndactyly, and triphalangeal malformed thumbs affected about 30% of the members. It is believed that this congenital hand deformity only occurs in an hereditary form.

Female↗
PubMed1984

[Hydrometrocolpos, polydactylia and congenital heart defect (the McKusick-Dungy-Kaufman syndrome)].

The McKusick-Dungy-Kaufman syndrome is characterized by hydrometrocolpos, polydactyly and congenital heart disease. Two of these 3 main symptoms should be present for the diagnosis. Associated anomalies are mainly found in the urogenital tract, the gastro-intestinal tract and the skeletal system. On the basis of 2 patients and the literature the clinical features and the genetic aspects of this syndrome are reviewed. The clinical variability and the severity of the syndrome are stressed. Evidence for an autosomal recessive inheritance is given. Because of the clinical variability it seems preferable to use the term complex rather than syndrome.

Abnormalities, Multiple↗
PubMed1982

Sideroblastic anaemia. A review of seven paediatric cases.

Sideroblastic Anaemias are characterised by a) chronic hypochromic anemia, b) ringed sideroblasts in the bone marrow, c) an increase in total body iron, d) ineffective erythropoiesis and e) often abnormal concentrations of F.E.P. A classification of Sideroblastic Anaemia is given and the pathophysiology of Sideroblastic Anaemia is discussed. A series of seven paediatric cases with Sideroblastic Anaemia is presented and the results of studies of the iron, vitamin B6 and porphyrin metabolism are discussed. In two cases arguments for an ALA-synthetase deficiency are given. All five males were diagnosed as hereditary X-linked Sideroblastic Anaemia, one female as I.R.S.A. and the other female, who showed the features of the X-linked type, as congenital Sideroblastic Anaemia.

5-Aminolevulinate Synthetase↗