Clinical and biochemical features associated with BCS1L mutation.

Our study describes a novel phenotype in a series of nine Saudi patients with lactic acidosis, from four consanguineous families three of which are related. Detailed genetic studies including linkage, homozygosity mapping and targeted sequencing identified a causative mutation in the BCS1L gene. All affected members of the families have an identical mutation in this gene, mutations of which are recognized causes of Björnstad syndrome, GRACILE syndrome and a syndrome of neonatal tubulopathy, encephalopathy, and liver failure (MIM 606104) leading to isolated mitochondrial respiratory chain complex III deficiency. Here we report the appearance of a novel behavioral (five patients) and psychiatric (two patients) phenotype associated with a p.Gly129Arg BCS1L mutation, differing from the phenotype in a previously reported singleton patient with this mutation. The psychiatric symptoms emanated after childhood, initially as hypomania later evolving into intermittent psychosis. Neuroradiological findings included subtle white matter abnormalities, whilst muscle histopathology and respiratory chain studies confirmed respiratory chain dysfunction. The variable neuro-psychiatric manifestations and cortical visual dysfunction are most unusual and not reported associated with other BCS1L mutations. This report emphasizes the clinical heterogeneity associated with the mutation in BCS1L gene, even within the same family and we recommend that defects in this gene should be considered in the differential diagnosis of lactic acidosis with variable involvement of different organs.

A novel X-linked disorder with developmental delay and autistic features.

OBJECTIVE: Genomic duplications that lead to autism and other human diseases are interesting pathological lesions since the underlying mechanism almost certainly involves dosage sensitive genes. We aim to understand a novel genomic disorder with profound phenotypic consequences, most notably global developmental delay, autism, psychosis, and anorexia nervosa. METHODS: We evaluated the affected individuals, all maternally related, using childhood autism rating scale (CARS) and Vineland Adaptive scales, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) brain, electroencephalography (EEG), electromyography (EMG), muscle biopsy, high-resolution molecular karyotype arrays, Giemsa banding (G-banding) and fluorescent in situ hybridization (FISH) experiments, mitochondrial DNA (mtDNA) sequencing, X-chromosome inactivation study, global gene expression analysis on Epstein-Barr virus (EBV)-transformed lymphoblasts, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). RESULTS: We have identified a novel Xq12-q13.3 duplication in an extended family. Clinically normal mothers were completely skewed in favor of the normal chromosome X. Global transcriptional profiling of affected individuals and controls revealed significant alterations of genes and pathways in a pattern consistent with previous microarray studies of autism spectrum disorder patients. Moreover, expression analysis revealed copy number-dependent increased messenger RNA (mRNA) levels in affected patients compared to control individuals. A subset of differentially expressed genes was validated using qRT-PCR. INTERPRETATION: Xq12-q13.3 duplication is a novel global developmental delay and autism-predisposing chromosomal aberration; pathogenesis of which may be mediated by increased dosage of genes contained in the duplication, including NLGN3, OPHN1, AR, EFNB1, TAF1, GJB1, and MED12.

GM2 gangliosidosis in Saudi Arabia: multiple mutations and considerations for future carrier screening.

The GM2 gangliosidose, Tay-Sachs and Sandhoff diseases, are a class of lysosomal storage diseases in which relentless neurodegeneration results in devastating neurological disability and premature death. Primary prevention is the most effective intervention since no effective therapy is currently available. An extremely successful model for the prevention of GM2 gangliosidosis in the Ashkenazi Jewish community is largely attributable to the very limited number of founder mutations in that population. Consistent with our previous observation of allelic heterogeneity in consanguineous populations, we show here that these diseases are largely caused by private mutations which present a major obstacle in replicating the Ashkenazi success story. Alternative solutions are proposed which can also be implemented for other autosomal recessive diseases in our population.

Chromosome 12q24.31-q24.33 deletion causes multiple dysmorphic features and developmental delay: First mosaic patient and overview of the phenotype related to 12q24qter defects.

BACKGROUND: Genomic imbalances of the 12q telomere are rare; only a few patients having 12q24.31-q24.33 deletions were reported. Interestingly none of these were mosaic. Although some attempts have been made to establish phenotype/genotype interaction for the deletions in this region, no clear relationship has been established to date. RESULTS: We have clinically screened more than 100 patients with dysmorphic features, mental retardation and normal karyotype using high density oligo array-CGH (aCGH) and identified a ~9.2 Mb hemizygous interstitial deletion at the 12q telomere (Chromosome 12: 46,XY,del(12)(q24.31q24.33) in a severely developmentally retarded patient having dysmorphic features such as low set ears, microcephaly, undescended testicles, bent elbow, kyphoscoliosis, and micropenis. Parents were found to be not carriers. MLPA experiments confirmed the aCGH result. Interphase FISH revealed mosaicism in cultured peripheral blood lymphocytes. CONCLUSIONS: Since conventional G-Banding technique missed the abnormality; this work re-confirms that any child with unexplained developmental delay and systemic involvement should be studied by aCGH techniques. The FISH technique, however, would still be useful to further delineate the research work and identify such rare mosaicism. Among the 52 deleted genes, P2RX2, ULK1, FZD10, RAN, NCOR2 STX2, TESC, FBXW8, and TBX3 are noteworthy since they may have a role in observed phenotype.

Integrative and comparative genomics analysis of early hepatocellular carcinoma differentiated from liver regeneration in young and old.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third-leading cause of cancer-related deaths worldwide. It is often diagnosed at an advanced stage, and hence typically has a poor prognosis. To identify distinct molecular mechanisms for early HCC we developed a rat model of liver regeneration post-hepatectomy, as well as liver cells undergoing malignant transformation and compared them to normal liver using a microarray approach. Subsequently, we performed cross-species comparative analysis coupled with copy number alterations (CNA) of independent early human HCC microarray studies to facilitate the identification of critical regulatory modules conserved across species. RESULTS: We identified 35 signature genes conserved across species, and shared among different types of early human HCCs. Over 70% of signature genes were cancer-related, and more than 50% of the conserved genes were mapped to human genomic CNA regions. Functional annotation revealed genes already implicated in HCC, as well as novel genes which were not previously reported in liver tumors. A subset of differentially expressed genes was validated using quantitative RT-PCR. Concordance was also confirmed for a significant number of genes and pathways in five independent validation microarray datasets. Our results indicated alterations in a number of cancer related pathways, including p53, p38 MAPK, ERK/MAPK, PI3K/AKT, and TGF-beta signaling pathways, and potential critical regulatory role of MYC, ERBB2, HNF4A, and SMAD3 for early HCC transformation. CONCLUSIONS: The integrative analysis of transcriptional deregulation, genomic CNA and comparative cross species analysis brings new insights into the molecular profile of early hepatoma formation. This approach may lead to robust biomarkers for the detection of early human HCC.

Hormonal levels of leptin, insulin, ghrelin, and neuropeptide Y in lean, overweight, and obese Saudi females.

OBJECTIVE: To studied the relationship that exists between leptin, ghrelin, insulin, neuropeptide Y (NPY), anthropometric, and metabolic variables in Saudi females. METHODS: The study was conducted at the Department of Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Kingdom of Saudi Arabia from November 2004 to August 2005. One hundred and twenty-two Saudi females were divided into 3 body mass index (BMI) groups: lean (N=60), overweight (N=17), and obese (N=45). Fasting leptin, ghrelin, insulin, NPY and glucose concentrations were determined. RESULTS: Leptin levels in overweight and obese groups were significantly higher than those in lean group. Leptin levels showed a positive correlation with BMI in obese (0.81), overweight (0.78), and lean (0.48). In contrast, ghrelin concentration decreased in obese and overweight subjects compared to lean subjects. Ghrelin levels were negatively correlated with BMI in obese (-0.81), overweight (-0.58), and lean subjects (-0.62). Negative correlations were found between serum insulin and ghrelin concentrations in lean and obese subjects. Glucose and insulin levels were significantly higher in the obese group compared to controls. No differences were found in serum NPY between the 3 groups. CONCLUSION: Leptin levels increased remarkably with increasing BMI. A leptin resistance state seems to exist in many obese and overweight individuals. Ghrelin concentration was decreased in overweight and obese subjects. These data demonstrate a significant inverse relationship between ghrelin and leptin levels in overweight and obese subjects.

Novel mitochondrial DNA transversion mutation in transfer ribonucleic acid for leucine 2 (CUN) in a patient with the clinical features of MELAS.

We describe an 11-year-old Saudi boy who had an encephalopathy suggestive of mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes (MELAS). We screened his entire mitochondrial DNA coding region and detected one novel transversion point mutation at nt-12299 A > C in the transfer ribonucleic acid for leucine 2 (CUN) that is located in the anticodon loop. We believe that this mutation is the cause of his disease condition.

Ophthalmic manifestations of Sanjad-Sakati syndrome.

BACKGROUND: Sanjad-Sakati syndrome (SSS) is a rare disorder characterized by hypoparathyroidism, growth and developmental delay, and dysmorphism. The purpose of this report is to describe the ophthalmic manifestations of Sanjad-Sakati syndrome (SSS; hypoparathyroidism-mental retardation-dysmorphism syndrome, HRD) (OMIM 241410). PATIENTS: We included a total of 17 patients who were seen at two hospitals in Riyadh. METHODS: Each patient underwent a complete ophthalmologic evaluation including visual acuity assessment, orthoptic workup, slit-lamp biomicroscopy, intraocular pressure measurement, cycloplegic retinoscopy, funduscopy, corneal diameter, and axial length measurement. RESULTS: All 17 (100%) of the patients had normal visual acuity. All patients had microphthalmia with normal intraocular pressure. Eight (47%) of the patients had esotropia and four (23%) had exotropia. Ophthalmoscopy revealed tortuous retinal blood vessels in all patients. Hyperopic astigmatism was present in 16 (94%) patients. CONCLUSION: Patients with SSS display a variety of ocular findings including errors of refraction, strabismus, and retinal vascular tortuousity.

Biotin-responsive basal ganglia disease maps to 2q36.3 and is due to mutations in SLC19A3.

Biotin-responsive basal ganglia disease (BBGD) is a recessive disorder with childhood onset that presents as a subacute encephalopathy, with confusion, dysarthria, and dysphagia, and that progresses to severe cogwheel rigidity, dystonia, quadriparesis, and eventual death, if left untreated. BBGD symptoms disappear within a few days with the administration of high doses of biotin (5-10 mg/kg/d). On brain magnetic resonance imaging examination, patients display central bilateral necrosis in the head of the caudate, with complete or partial involvement of the putamen. All patients diagnosed to date are of Saudi, Syrian, or Yemeni ancestry, and all have consanguineous parents. Using linkage analysis in four families, we mapped the genetic defect near marker D2S2158 in 2q36.3 (LOD=5.9; theta=0.0) to a minimum candidate region (approximately 2 Mb) between D2S2354 and D2S1256, on the basis of complete homozygosity. In this segment, each family displayed one of two different missense mutations that altered the coding sequence of SLC19A3, the gene for a transporter related to the reduced-folate (encoded by SLC19A1) and thiamin (encoded by SLC19A2) transporters.

Recently available techniques applicable to genetic problems in the Middle East.

In this paper, we address the preventive health aspects of genetic problems in the Middle East and provide guidelines to prioritize preventive strategies. Applications of various novel genetic techniques such as comprehensive neonatal screening, high throughput heterozygote detection, preimplantation genetic diagnosis, Affymetrix systems, the NanoChip system and a new way of sensitive karyotyping for single-cell chromosome abnormalities are discussed. In conclusion, from the various genetic techniques available, each country should adopt strategies most suitable to its genetic needs and should prioritize the programs to be used in prevention.

Mitochondrial DNA nucleotide changes in non-arteritic ischemic optic neuropathy.

The authors sequenced the entire mitochondrial DNA coding region in a group of 19 patients with non-arteritic anterior ischemic optic neuropathy (NAION) and in 100 controls. Synonymous and nonsynonymous nucleotide changes were more common in NAION patients (p < 0.001). Twelve of these (11 novel) were potentially pathologic, nine of which altered moderately or highly conserved amino acids in the functional domain of the affected protein. Mitochondrial malfunction may be a risk factor for NAION.

Carnitine prevents cyclic GMP-induced inhibition of peroxisomal enzyme activities.

Peroxisomes, also termed as microbodies, are now known to carry out several specialized metabolic activities that are vital to cellular function. A defect in peroxisomal function leads to development of a fatal human disease, and a number of peroxisomal disorders are now linked to inherited peroxisomal enzyme abnormalities. Peroxisomal enzyme activities are also altered during pathophysiological conditions through various endogenously produced bio-molecules such as nitric oxide (NO). NO produced by cytokines or NO-donors is known to modulate peroxisomal functions, and these effects of NO are mediated through cGMP. We are reporting for the first time that L-carnitine (1-5 mm) prevents cGMP-mediated impairment of peroxisomal enzyme activities. Cyclic GMP (250-1000 muM) significantly inhibited (p < 0.01) the specific activities of catalase, acyl CoA oxidase and dihydroxyacetone-phosphate acyltransferase (DHAPATase) in human dermal fibroblasts, and treatment of cells with 1-5 mM of carnitine significantly (p < 0.001) reduced the inhibitory effects of cGMP on peroxisomal enzyme activities. These findings suggest that carnitine, previously thought to participate only in fatty acid oxidation, may in fact be regulating other cellular events including oxidative stress, and could possibly be used to correct cytokine-impaired peroxisomal functions.

Nitric oxide promotes mitogen-induced dna synthesis in human dermal fibroblasts through cGMP.

1. Nitric oxide (NO) is a free radical with multiple functions in cellular pathophysiology. Nitric oxide has been proven to play an important role in wound healing; however, the mechanisms by which NO may promote wound healing are not clearly understood. We have investigated the effect of NO on growth factor-induced DNA synthesis in human dermal fibroblasts to suggest interactions between growth factors and NO as a possible mechanism for the role of NO in wound healing. 2. The NO donor sodium nitroprusside (SNP) significantly (P < 0.001) increased fetal bovine serum-induced thymidine incorporation into the DNA of human dermal fibroblasts. The maximal comitogenic concentration of SNP (100 micro mol/L) was also found to significantly (twofold; P < 0.01) enhance fibroblast growth factor- or platelet-derived growth factor-induced DNA synthesis. 3. Nitric oxide treatment significantly increased the production of cGMP. 8-Bromo-cGMP, a stable structural analogue of cGMP, was found to markedly potentiate (P < 0.001) the growth factor-induced DNA synthesis. 4. This study concludes that NO and cGMP promote growth factor-induced DNA synthesis in dermal fibroblasts, suggesting another possible mechanism by which NO may promote skin wound healing.

A new era for preventive genetic programs in the Arabian Peninsula.

In the Arabian Peninsula, high percentages of consanguineous marriages and the tribal nature of marriages have resulted in high incidence of genetically based disorders. The successful management of these disorders incurs a high financial cost, which is a great burden on the health care system. The practical solution to this problem is through prevention. Prevention of genetic disorders should be the utmost public health concern especially where these disorders are prevalent. Preventive genetics became possible with the advent of biochemical and molecular technologies. Biochemical neonatal screening based on tandem mass spectrometry technology and molecular technologies such as sequencing, DNA microarray and nucleic acid hybridization techniques are steadily being transferred to clinical practice. Preventive genetics could be best achieved through establishment of databases for common genetic disorders, premarital diagnosis, and pre-implantation genetic diagnosis and by genetic counseling. These preventive measures must take into account the social and cultural aspects.

A simple, rapid test for the differential diagnosis of glycogen storage disease type 3.

BACKGROUND: Type 3 glycogen storage disease is an inborn error of metabolism in young infants that often requires extensive workup. However, this disease manifests with few symptoms other than hepatosplenomegaly. At adolescence, this disease may cause myopathy and cardiomyopathy. Since a significant portion of referrals to pediatrics is for evaluation of a hepatosplenomegaly, the differential diagnosis of this disease assumes importance. METHODS: The clinical and biochemical findings in 26 patients with the type 3 glycogen storage disease were investigated. Biochemical parameters included ALT, AST, total CK and CK-MB. RESULTS: Changes in ALT, AST and total CK were observed to varying degrees. However, CK was found to be a diagnostic indicator for type 3 glycogen storage disease and appears to be a pathognomic marker. CONCLUSIONS: Use of CK may reduce the need for extensive diagnostic profiles and aid in the rapid identification and initiation of management for patients presenting with hepatosplenomegaly.