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Biomedical subjects

H Dar

Publications and source records attributed to H Dar.

At least 37 records · Page 2Linked to original sources

Ataxia-telangiectasia: linkage analysis in highly inbred Arab and Druze families and differentiation from an ataxia-microcephaly-cataract syndrome.

Ataxia-telangiectasia (A-T) is a progressive autosomal recessive disease featuring neurodegeneration, immunodeficiency, chromosomal instability, radiation sensitivity and a highly increased proneness to cancer. A-T is ethnically widespread and genetically heterogeneous, as indicated by the existence of four complementation groups in this disease. Several "A-T-like" genetic diseases share various clinical and cellular characteristics with A-T. By using linkage analysis to study North American and Turkish A-T families, the ATA (A-T, complementation group A) gene has been mapped to chromosome 11q23. A number of Israeli Arab A-T patients coming from large, highly inbred families were assigned to group A. In one of these families, an additional autosomal recessive disease was identified, characterized by ataxia, hypotonia, microcephaly and bilateral congenital cataracts. In two patients with this syndrome, normal levels of serum immunoglobulins and alpha-fetoprotein, chromosomal stability in peripheral blood lymphocytes and skin fibroblasts, and normal cellular response to treatments with X-rays and the radiomimetic drug neocarzinostatin indicated that this disease does not share, with A-T, any additional features other than ataxia. These tests also showed that another patient in this family, who is also mentally retarded, is affected with both disorders. This conclusion was further supported by linkage analysis with 11q23 markers. Lod scores between A-T and these markers, cumulated over three large Arab families, were significant and confirmed the localization of the ATA gene to 11q23. However, another Druze family unassigned to a specific complementation group, showed several recombinants between A-T and the same markers, leaving the localization of the A-T gene in this family open.

Ataxia↗

The association between unexplained second-trimester maternal serum hCG elevation and pregnancy complications.

OBJECTIVE: We conducted this cohort analytic study to determine whether women with unexplained elevations of maternal serum hCG at 16-20 weeks' gestation are at increased risk for pregnancy complications and adverse perinatal outcomes. METHODS: The inclusion criteria were a singleton gestation, a confirmed gestational age, and an hCG level greater than 2.5 multiples of the median (MOM). The exclusion criteria were fetal anomalies, an abnormal karyotype, and a maternal serum alpha-fetoprotein (MSAFP) level greater than 2.5 MOM. A group of randomly selected women with normal hCG and MSAFP levels served as controls. RESULTS: Of the 6011 women screened, 284 (4.7%) had an unexplained elevated hCG level. Patients with elevated levels of hCG had a significantly higher risk for hypertension (odds ratio 4.4; 95% confidence interval [CI] 1.9-10) and fetal growth restriction (odds ratio 2.8; 95% CI 1-7). Women with hCG levels greater than 4 MOM also had an increased risk of preterm delivery (odds ratio 3.3; 95% CI 1.3-8.2). CONCLUSION: Pregnancies with unexplained elevated hCG levels should be regarded as high-risk pregnancies and managed accordingly.

Chorionic Gonadotropin↗

Free proximal trisomy 21 in the mother and malformation syndrome in the son.

We report on a new case of duplication of the proximal part of the long arm of chromosome 21. The proposita presents normal mental development, no trisomy 21 manifestations; on the contrary, she had a few monosomy 21-like stigmata. She gave birth to a severely malformed infant with a pattern of malformations suggesting a partial 21-monosomy syndrome, but with a 46,XY normal karyotype in his peripheral blood lymphocytes. The findings are explained in the following way: the infant probably had originally a 47,XY,+21q- karyotype like his mother. Post zygotic nondisjunctional events produced a prevalent 46,XY,21q- line responsible for the severe malformations and the normal 46,XY line found in his blood lymphocytes.

Abnormalities, Multiple↗

Brain tumor as a second malignant neoplasm following neuroblastoma stage IV S.

A rare brain tumor (spongioblastoma polare) occurring 7 years after treatment of neuroblastoma stage IV S is reported. The literature concerning the occurrence of a second cancer in children exposed to mutagenic therapy for their initial tumor is reviewed, and genetic and environmental factors are discussed. Diminishing aggressiveness of the treatment in childhood cancer with good prognosis should be considered. Continuous follow-up of children cured of cancer is warranted.

Abdominal Neoplasms↗

The dilemma of chromosomal mosaicism in chorionic villus sampling--'direct' versus long-term cultures.

Chromosomal mosaicism is one of several unanswered dilemmas in first-trimester prenatal diagnosis. We report the course of a pregnancy in which a normal karyotype was detected on direct CVS preparation and fetal blood, 100 per cent trisomy 21 in one long-term CVS culture, and low-rate trisomy 21 mosaicism in a second long-term CVS culture and amniocentesis. The phenotypically normal infant had a 6 per cent mosaicism of trisomy 21. It appears that a persistent low-rate mosaicism in different tissues may be indicative of the true status of the fetus.

Adult↗

The neurofibromatosis-Noonan syndrome: genetic heterogeneity versus clinical variability. Case report and review of the literature.

We report on a discordant twin male with neurofibromatosis and manifestations of the Noonan syndrome. He has multiple café-au-lait spots and axillary freckling, relative macrocephaly, ptosis, mid-face hypoplasia, short neck and pulmonic stenosis. The presence of neurofibromatosis associated with Noonan syndrome phenotype in our patient raises the question of a unique disorder sharing characteristics of both conditions.

Adolescent↗

[Inborn errors of metabolism: lessons from a clinical case].

Dramatic advances in recent years in the diagnosis and treatment of inborn errors of metabolism (IEM) make it imperative for the physician to be both aware of their occurrence and acquainted with their clinical presentations. Many may present with symptoms and signs common to sick infants, such as refusal to feed, vomiting and convulsions. Failure to include IEM in the differential diagnosis may have grave consequences, because only prompt recognition and appropriate treatment of a metabolic crisis can help prevent irreversible brain damage or death. We describe a 3-week-old female infant, eventually diagnosed as having an IEM (3-hydroxy-3-methyl-glutaric aciduria), who was admitted to various hospitals and died during her last admission. We focused on the clinical and laboratory findings of each of the first 2 admissions which might have provided clues to the true nature of the illness had the clinicians been aware of the possibility of IEM. Patients with IEM are generally managed in specialized centers; however, the responsibility for initial recognition and immediate treatment of a metabolic emergency lies with the primary physician. The purpose of our case presentation and the discussion of the lessons derived from it, is to prompt the clinician to an awareness and understanding of a subject that used to be considered reserved for specialists. In fact, all that is needed is clinical alertness and the performance of certain well-focused, simple laboratory tests for IEM.

Amino Acid Metabolism, Inborn Errors↗

Paracentric inversion of Xq and ovarian dysfunction.

We report on a paracentric inversion X(q13 q24) in a 20-year-old woman with ovarian dysfunction. The findings add evidence on the role of breakpoints in Xq13 and Xq24 in causing ovarian dysfunction. A review of the published data on paracentric inversion of chromosome X is included.

Adult↗

The clinical significance of multiple hair whorls and their association with unusual dermatoglyphics and dysmorphic features in mentally retarded Israeli children.

The prevalence of multiple hair whorls in a group of mentally retarded patients was 8% as opposed to 3.6% in a group of healthy children. A statistically significant relationship was demonstrated between mental retardation, multiple hair whorls, more than two dysmorphic features, and unusual dermatoglyphics. The results confirm the importance of multiple hair whorls as a genuine dysmorphic feature. The significance of these markers in the evaluation of mentally retarded subjects is discussed, with special reference to the timing of the fetal insult.

Abnormalities, Multiple↗

[Non-cardiac pulmonary edema: an enigma today].

Pulmonary oedema is caused by an excessive accumulation of interstitial fluid in the lungs: in the case of left ventricular failure, oedema arises due to an increase in capillary hydrostatic pressure. Non-cardiac oedema, on the other hand, is brought about by a change in alveolar capillary membrane permeability. Although the causes are different, namely respiratory distress syndrome in adults, altitude-induced pulmonary oedema, oxygen toxicity, medication, metabolic changes, etc., the result is the same, i.e. damage to the alveolar capillary membrane. This damage appears to be brought about by two factors: complement activation and damage to the blood clotting mechanism. The difference between cardiac and non-cardiac pulmonary oedema is difficult to gauge. If pulmonary cone pressure is normal or low, and if the oedematous fluid/plasma protein ratio is greater than 0.7, the oedema is non-cardiac in origin. Treatment is carried out with the aim of repairing the alveolar capillary membrane and preventing extension of the damage. Respiratory insufficiency is treated by a mechanical respirator, applying positive pressure at the end of expiration. Fluid administration is adjusted according to pulmonary cone pressure levels. Opinions are still divided over whether to administer crystalline or colloidal solutions, steroids or protease inhibitors.

Adrenal Cortex Hormones↗

The Groll-Hirschowitz syndrome.

Two sisters showed a similar disorder with cachexia, sensory deafness, and upper gastrointestinal abnormalities. The family pedigree suggests autosomal recessive inheritance of the disorder. Demyelinization demonstrated by a peripheral nerve biopsy may explain the basis for the manifestations. Only one family with this unique syndrome has been reported in the literature. The term "The Groll-Hirschowitz Syndrome" has been suggested, named after the two physicians who first described this condition.

Adult↗

Prevalence of gestational and perinatal insults in brain-damaged children.

The value of utilizing the analysis of unusual dermatoglyphic patterns and of microscopic dental enamel abnormalities as nonspecific registers of fetal and perinatal insult was investigated in brain-damaged children. Positive findings were demonstrated in 82% of the brain-damaged group and in 17% of healthy controls (P less than 0.001). This confirms that most brain damage in children occurs during pregnancy. The limited correlation between recorded potential damaging events during pregnancy and the appropriate markers of fetal/perinatal insult suggests that the data available are inadequate for identifying the causes of brain damage. The implications of these observations are discussed with regard to determining the etiology of brain damage.

Brain Damage, Chronic↗

Diagnostic approach to the etiology of mental retardation.

The clinical and laboratory investigation of the etiology of mental retardation is discussed. By clinically determining the stage of onset of the mental retardation, it is possible to dispense with a large number of special investigations. It is concluded that the laboratory is chiefly of value in confirming clinical suspicions, and that only rarely will random or routine testing yield an unexpected diagnosis. The possible exception is dermatoglyphic analysis in nondysmorphic, idiopathically retarded patients. This examination demonstrated probable antenatal causative factors in a high percentage of children with retardation of intrauterine origin. If further investigation were to confirm the findings, then this simple examination should be included in the routine evaluation of these cases.

Child, Preschool↗

Dermatoglyphic and palmar-crease alterations as indicators of early intra-uterine insult in mental retardation.

A comparative study of unusual dermatoglyphic and palmar patterns revealed significant differences between the frequencies of certain patterns among 200 congenitally affected mentally retarded children and 500 normal controls. A scoring method demonstrating the significance of eight unusual patterns as non-specific indicators of early intra-uterine fetal insult was devised. 10 per cent of the children previously classified as idiopathically mentally retarded were shown to have been exposed to early intra-uterine insult. Dermatoglyphic and palmar-crease analysis should be included as a routine investigation for children with mental retardation of unknown cause.

Abnormalities, Multiple↗