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Biomedical subjects

H Nazer

Publications and source records attributed to H Nazer.

At least 19 recordsLinked to original sources
PubMed2000

Identification of novel mutations in Arabs with cystic fibrosis and their impact on the cystic fibrosis transmembrane regulator mutation detection rate in Arab populations.

UNLABELLED: The cystic fibrosis transmembrane regulator (CFTR) gene in Arab patients with cystic fibrosis (CF) (sweat chloride > 60 mmol/l) from 61 unrelated families was screened for mutations in exons 3, 4, 5, 7, 10, 11, 16 and 19 and for mutations W1282X, N1303K and 3,849 + 10kbC --> T. Eight novel mutations were identified. These are: in exon 4: a) 425del42 (an in-frame 42 bp deletion that removes 14 amino acids and causes Gln98 --> His at the point of deletion), b) 475G --> T (Glu115 --> Stop) and c) 548A --> T (His139 --> Leu); in intron 5,711 + 1G --> A (splice site mutation); in exon 10, 1548delG (deletion of a "G" nucleotide causing a frameshift mutation that alters the amino acid sequence at residue 473 and results in translation termination at residue 526); in exon 11, a) 1729T --> C (Ph533E --> Leu) and b) 1,811 + 2 (splice site mutation) and finally in exon 19,3361A --> T (Lys1177 --> Stop). All mutations were detected by heteroduplex analysis and identified by sequencing. Of more than 850 known CFTR mutations, only 9 were encountered. The comparative frequencies of the most common mutations are: 1548delG> 1123V = deltaF508 = 3,120 + 1G --> A > H139L. Screening for these five mutations identifies 60% of the CF alleles in Arab populations. The novel mutation 1548delG is the most frequent (17%) among Arabs. CONCLUSION: Novel Arab-specific mutations were identified in the CFTR gene underlying cystic fibrosis. As a result of this study, the CFTR mutation detection rate among Arabs with cystic fibrosis is now comparable to that of other populations.

Alleles↗
PubMed2000

The bile acid synthetic gene 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase is mutated in progressive intrahepatic cholestasis.

We used expression cloning to isolate cDNAs encoding a microsomal 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase (C(27) 3beta-HSD) that is expressed predominantly in the liver. The predicted product shares 34% sequence identity with the C(19) and C(21) 3beta-HSD enzymes, which participate in steroid hormone metabolism. When transfected into cultured cells, the cloned C(27) 3beta-HSD cDNA encodes an enzyme that is active against four 7alpha-hydroxylated sterols, indicating that a single C(27) 3beta-HSD enzyme can participate in all known pathways of bile acid synthesis. The expressed enzyme did not metabolize several different C(19/21) steroids as substrates. The levels of hepatic C(27) 3beta-HSD mRNA in the mouse are not sexually dimorphic and do not change in response to dietary cholesterol or to changes in bile acid pool size. The corresponding human gene on chromosome 16p11.2-12 contains six exons and spans 3 kb of DNA, and we identified a 2-bp deletion in the C27 3beta-HSD gene of a patient with neonatal progressive intrahepatic cholestasis. This mutation eliminates the activity of the enzyme in transfected cells. These findings establish the central role of C(27) 3beta-HSD in the biosynthesis of bile acids and provide molecular tools for the diagnosis of a third type of neonatal progressive intrahepatic cholestasis associated with impaired bile acid synthesis.

3-Hydroxysteroid Dehydrogenases↗
PubMed2000

99mTc-human serum albumin scans in children with protein-losing enteropathy.

UNLABELLED: Protein-losing enteropathy (PLE) can be diagnosed scintigraphically using 99mTc-human serum albumin (HSA) scans. METHODS: To evaluate the usefulness of this method in detecting enteric protein loss, we retrospectively reviewed the 99mTc-HSA scans of 18 children presenting consecutively with PLE. RESULTS: Enteric 99mTc-HSA uptake was noted in 12 patients (8 boys, 4 girls) with a mean age of 7.4 y. Early dynamic images showed abdominal uptake that was most likely in the small bowel in 91% of the scans. Delayed images showed abnormal accumulation that was localized in the colon in 73% and in the small bowel in 27% of the scans. A 4-mo follow-up scan obtained in 3 patients showed reduced HSA uptake after a high-protein, low-fat, medium-chain triglyceride oil-based diet and fat-soluble vitamins. Mean serum albumin, total protein, gammaglobulin, and calcium levels were significantly decreased. Ten patients (from 4 families) were diagnosed to have primary intestinal lymphangectasia. One patient had active Salmonella enterocolitis, and 1 had giardiosis. 99mTc-HSA was normal in the remaining 6 patients (3 boys, 3 girls) with a mean age of 3.5 y (range, 2-5 y). Mean serum albumin, total protein, gammaglobulin, and calcium levels were less decreased than those of the first group. Five of these patients had primary intestinal lymphangactesia (associated with infantile systemic hyalinosis in 1 patient). The remaining patient had normal duodenal biopsy, and the cause of protein loss remained unknown. CONCLUSION: The 99mTc-HSA scan is useful in the evaluation of children with PLE, especially those with severe hypoproteinemia and hypoalbuminemia, presumably reflecting a high rate of protein loss.

Child↗
PubMed1998

Crigler-Najjar syndrome in Saudi Arabia.

Crigler-Najjar (CN) syndrome is a congenital familial nonhemolytic jaundice associated with high level of unconjugated bilirubin due to deficient uridine diphosphate glucuronosyltransferase (UDPG-T) activity in the liver. The aim of this report is to emphasize the need for increased awareness of this potentially fatal condition unless diagnosed early and managed appropriately. Between 1986-1994, 12 patients (8 males and 4 females) were diagnosed at our hospital with CN syndrome. Jaundice was detected in the first few days of life in all but one, in whom detection was delayed for two weeks and resulted in kernicterus. Exchange transfusions were necessary in six cases. Consanguinity was present in 11 patients, eight of whom were the offspring of first cousins. None of the patients responded to phenobarbital therapy alone, which reflects the severity of their disease. Six patients required only phototherapy while the remaining six patients required a combination of phenobarbital and phototherapy. Percutaneous liver biopsy, performed in 10 patients, showed minimal and focal cholestasis in eight, while the remaining two had a normal histological picture. Almost complete absence of the activity of UDPGT in the liver was reported in seven cases. Kernicterus developed in five cases. It is concluded that CN syndrome remains a potentially fatal condition unless diagnosed early and managed appropriately. The recent adoption of liver segment transplantation, whether orthotopic or living-related, has saved affected patients the daily long hours of phototherapy. One of our patients successfully underwent living-related segmental liver transplantation.

Child, Preschool↗
PubMed1998

Genetic background of congenital chloride diarrhea in high-incidence populations: Finland, Poland, and Saudi Arabia and Kuwait.

Congenital chloride diarrhea (CLD) is an inherited intestinal disorder caused by mutations in the down-regulated in adenoma gene. In Finland, the disease is prevalent because of a founder effect, and all but one of the CLD-associated chromosomes carry the same mutation, V317del. In Poland, another area with a high incidence of CLD, as many as seven different mutations have been detected so far. A third known cluster of CLD, around the Persian Gulf, has not been genetically studied. We studied the allelic diversity of CLD in Poland, in Saudi Arabia and Kuwait, and in three isolated families from North America and Hong Kong. Altogether, eight novel mutations were identified, making a total of 19 known CLD gene mutations. The Polish major mutation I675-676ins was found in 47% of the Polish CLD-associated chromosomes. Haplotype analysis and clustering of the I675-676ins mutation supported a founder effect and common ancestral origin. As in Finland, a major founder effect was observed in Arab patients: 94% of the CLD-associated chromosomes carried a nonsense mutation, G187X, which occurred in either a conserved ancestral haplotype or its derivative. Our data confirm that the same locus is mutated in all cases of CLD studied so far. In Poland, a relatively common founder mutation is likely to highlight a set of rare mutations that would very rarely produce homozygosity alone. This suggests that mutations in the CLD locus are not rare events. Although the disease is thought to be rare, undiagnosed patients may not be uncommon.

Chlorides↗
PubMed1997

High levels of (24S)-24-hydroxycholesterol 3-sulfate, 24-glucuronide in the serum and urine of children with severe cholestatic liver disease.

Extracts of urine and serum from children with cholestatic liver disease were analyzed by fast atom bombardment (FAB) mass spectrometry. About half of all spectra showed a peak at m/z 657, compatible with the presence of a glucuronidated cholestenediol sulfate. Separation by ion exchange chromatography before and after solvolysis and treatment with beta-glucuronidase, combined with analyses by gas chromatography-mass spectrometry and FAB mass spectrometry with collision-induced dissociation, showed that the major compound responsible for the peak at m/z 657 was (24S)-24-hydroxycholesterol 3-sulfate, 24-glucuronide. The double conjugate of 27-hydroxycholesterol was also identified and double conjugates of cholestene- and cholestanetriols were also present. Semiquantitative analyses of the double conjugate of 24-hydroxycholesterol in patients whose FAB spectra showed a peak at m/z 657 indicated serum levels of 2-18 microM and a daily urinary excretion of 0.1-2.7 mumol/24 h. Eleven of 13 studied patients with a prominent peak at m/z 657 in the FAB spectra of their serum or urine either underwent liver transplantation or died. It is concluded that double conjugation of hydroxysterols with sulfuric and glucuronic acids can be an important metabolic pathway, particularly for (24S)-24-hydroxycholesterol. It is speculated that serious cholestatic liver disease may induce an increased formation and release of (24S)-24-hydroxycholesterol from brain (Lütjohann et al. 1996, Proc. Nutl. Acad. Sci. USA. 93: 9799-9804) with subsequent extracerebral conjugation with sulfuric and glucuronic acids.

Biomarkers↗
PubMed1996

Severe dental aberrations in familial steroid dehydrogenase deficiency: a new association.

Severe numerical dental aberrations are rare, and are most often seen as a part of certain syndromes. We here report on a Saudi Arabian family where first-cousin marriages have caused numerical and structural dental abnormalities linked to autosomal recessively inherited liver diseases. The two latest affected children in this family have had their liver defect successfully treated with fat-soluble vitamins and chenodeoxycholic acid, enabling us to study their dental development. One boy exhibits 11 supernumerary teeth, a general hypomineralisation and enamel hypoplasia, while an affected cousin successfully diagnosed at an early age, so far, only suffers from structural enamel defects. The children are otherwise healthy. There is no resemblance to any known syndromes. We suggest that the supernumerary teeth and the liver disease are caused by the same genetic defect, and represent a new association. The hypomineralisation, however, is most likely to result from vitamin deficiency secondary to malabsorption during the first years of life, before successful treatment was instituted.

3-Hydroxysteroid Dehydrogenases↗
PubMed1995

No linkage to the 3 beta-HSD gene cluster in a kindred affected with 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase deficiency and early onset hepatic failure.

We studied the segregation of the genes for 3 beta-hydroxy-C19/21-steroid dehydrogenase types I and II (3 beta-HSD I and II) in a consanguineous family affected with 3 beta-hydroxy-delta 5-C27-steroid dehydrogenase (3 beta-OH-C27-SD) deficiency. The results show that the C27 and C19/21 steroid dehydrogenase activities are encoded by distinct genes that are not in genetic linkage. Further kindreds would assist in screening for linkage of 3 beta-OH-C27-SD to other members of the 3 beta-hydroxysteroid dehydrogenase gene family.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Cystic fibrosis and the liver--a Saudi experience.

Cystic fibrosis (CF) is an autosomal recessive disorder that is reported frequently among Caucasians. In view of the high rate of consanguinity in Saudi Arabia and the high number of children dying so young, many Saudi infants with CF remain undiagnosed owing to lack of clinical suspicion and proper diagnostic facilities. Over a 6-year period (1986-1992), we have made a diagnosis of CF in 36 cases. The aim of this report is to increase awareness of the hepatic presentation of CF in the developing word. Nine patients (25%) were originally referred to us as having liver disorders but subsequent investigations confirmed the diagnosis of CF. The referral diagnoses, number of patients in parentheses, were jaundice for investigation (four), glycogen storage disease (three), hepatomegaly for investigation (one) and neonatal hepatitis (one). Liver biopsies, obtained in five cases, demonstrated portal fibrosis and some steatosis. Consanguinity was present in eight cases, two were siblings. Four patients died. Three families had previously lost seven siblings during infancy with clinical features consistent with CF. It is concluded that hepatic presentation among Saudi patients with CF is relatively common, with serious sequelae.

Biopsy↗
PubMed1993

Magnetic resonance imaging of the brain in Wilson's disease.

Eight patients with Wilson's disease (WD) were studied by magnetic resonance imaging (MRI) of the brain; seven also underwent X-ray computed tomography (CT) of the brain. We describe the changes in the brain and try to correlate them with the clinical manifestations and progress of the disease. Six patients were symptomatic, with predominantly neurological problems. Two were asymptomatic, diagnosed upon screening siblings of index cases. Of the six symptomatic patients, five had basal ganglia lesions, combined in four with brain stem changes; in one with only brain stem abnormalities, clinical findings were minimal despite pronounced MRI changes. In three patients MRI abnormalities regressed following chelating therapy. MRI can contribute to documentation of early neurological involvement in WD, especially in patients with no abnormalities on CT. However, MRI changes may not correlate with clinical presentation or response to therapy.

Adolescent↗
PubMed1993

Resolution of cystic hygroma, hydrops fetalis, and fetal anemia.

Cystic hygroma with hydrops fetalis is considered to have grave prognosis. This report describes a case of resolution of cystic hygroma, hydrops fetalis, and fetal anemia in a female fetus with a normal karyotype. Cystic hygroma and hydrops fetalis were noted on a routine ultrasound examination at 27 weeks' gestation in a fetus with 46,XX karyotype. Fetal blood sampling at 30 weeks' gestation showed fetal hemoglobin of 64 gm/liter. Intrauterine blood transfusion at 30 weeks' gestation raised the hemoglobin level to 91 gm/liter. Serial ultrasound studies demonstrated complete resolution of cystic hygroma and marked reduction of hydrops fetalis. The fetus was delivered at term. She was noted to have redundant skin of posterior neck and edema of upper and lower extremities. Hemoglobin level at birth was 151 gm/liter. Regular follow-up to 6 months of age showed the baby to have normal growth and development, with the return of the skin at the posterior neck to normal.

Adult↗
PubMed1993

Transverse myelitis in a child with Down's syndrome and schistosomal colitis.

This is a report of an 11-year-old Saudi child with Down's syndrome who presented with a 3-month history of diarrhoea, anal fissures and bleeding per rectum. The child was investigated in a local hospital and found to have evidence of colitis. He was referred to our hospital for further investigation and management. Six weeks prior to transfer, the child developed weakness of the lower limbs resulting in inability to walk. The child was found to have Schistosoma mansoni colitis complicated by spinal cord involvement presenting as transverse myelitis. Two 1-day courses of therapy with praziquantel resulted in a satisfactory recovery, enabling the child to walk by himself.

Child↗
PubMed1992

Acute hydrops of the gallbladder in childhood.

Acute hydrops of the gallbladder (AHGB) is a rare paediatric disease being diagnosed with increased frequency due to its association with other illnesses and the availability of ultrasonography. The symptoms and signs of AHGB include abdominal pain, vomiting, abdominal mass and/or tenderness. As these clinical features mimic the more common surgical conditions such as acute appendicitis, intussusception and volvulus, some cases are still diagnosed only at laparotomy. Diagnosis is established by ultrasonography of the abdomen demonstrating normal biliary ducts and a distended gallbladder without calculi or congenital malformation. The aetiology of acute hydrops of the gallbladder is unknown but may be multifactorial. Treatment varies from non-operative management to surgical intervention.

Acute Disease↗