Comparing REM- and NREM-Related Obstructive Sleep Apnea in Jordan: A Cross-Sectional Study.

Obstructive sleep apnea (OSA) is a common disorder that includes an intermittent mechanical obstruction of the upper airway during sleep, which can occur either during rapid eye movement (REM) phase or non-REM (NREM) phase. In this study, we aim to evaluate the differences in demographic and polysomnographic features between REM- and NREM-related OSA in a Jordanian sample, using both the broad and the restricted definitions of REM-related OSA. All patients who were referred due to clinical suspicion of OSA and underwent sleep study were screened. We included patients with a diagnosis of OSA who had Apnea-Hypopnea Index (AHI) greater than or equal to five. We classified patients into REM-related OSA according to either the broad definition (AHIREM/AHINREM ≥ 2) or the strict definition (AHIREM > 5 and AHINREM < 5 with a total REM sleep duration of at least 30 minutes), and patients with AHIREM/AHINREM less than two were classified as NREM-related OSA. A total of 478 patients were included in this study with a mean age of 55.3 years (±12.6). According to the broad definition of REM-related OSA, 86 (18%) of OSA patients were classified as having REM-related OSA compared to only 13 (2.7%) patients according to the strict definition. Significant differences were found between both NREM-related OSA and REM-related OSA according to the broad and to the strict definitions for arousal index (p < 0.001 and p < 0.032), respectively, duration of saturation below 90% (p < 0.001 for both), and saturation nadir (p < 0.036 and p < 0.013), respectively. No significant differences were found between this group and other OSA patients regarding age, BMI, ESS, and snoring. Our study showed that the stricter the definition for REM-related OSA, the milder the associated clinical changes.

Evaluation of α-D-ribofuranose (D-ribose) toxicity after intravenous administration to rabbits.

Rapid intravenous administration of D-ribose may result in a significant reduction in cellular damage in patients with sudden ischemic insults. The development of an effective and clinically safe therapeutic regimen using the intravenous route in critically ill patients especially with cardiac diseases requires a comprehensive assessment of potential toxic effects of the drug in laboratory animals and in human beings. The potential clinical, behavioral, hematological, biochemical, gross pathological and histological toxic effects associated with the intravenous administration of D-ribose in rabbits for 28 days were evaluated in this study. Except for an increase in neutrophil percentage in male rabbits in the D-ribose-treated groups, there were no statistically significant toxic effects induced by daily intravenous administration of the drug in male and female rabbits. Results of this study suggest that D-ribose administered intravenously for 28 days in the rabbit exhibited no toxicity at 420 mg/kg.

Angiotensin-converting enzyme gene insertion/deletion polymorphism in Kuwaiti children with retinopathy of prematurity.

Retinopathy of prematurity (ROP) is a disease characterized by neovascularization which occurs in infants with short gestational age and low birth weight and can lead to retinal detachment and blindness. In a proportion of ROP cases, the disease progresses to advanced stages despite rigorous intervention. The genotypes for angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism were determined in 181 premature Kuwaiti infants using a polymerase chain reaction (PCR) method. The incidence of different I/D genotypes was compared in ROP cases (n = 74) and non-ROP controls (n = 107) and within 2 subgroups of ROP patients: (1) in which ROP regressed spontaneously (stages 1-3, n = 53), and (2) in which ROP progressed to advanced stages (stages 4 and 5, n = 21). When the ROP cases were considered collectively as one group, the incidence of the DD genotype was almost identical to that of non-ROP controls. The incidence of heterozygous ID genotype was higher in non-ROP controls. The incidence of the II genotype was higher in ROP cases compared to non-ROP controls (p < 0.01). In contrast to this, when ROP cases were divided in 2 subgroups the incidence of the DD genotype was significantly higher in advanced stage ROP cases compared to spontaneously regressing ROP cases (p < 0.04). The incidences of ID and II genotypes were not significantly different amongst the 2 subgroups of ROP patients.

A C597-->A polymorphism in the Norrie disease gene is associated with advanced retinopathy of prematurity in premature Kuwaiti infants.

Retinopathy of prematurity (ROP) is a retinal vascular disease which occurs in infants with a short gestational age and low birth weight and may lead to retinal detachment and blindness. In some premature infants, ROP progresses to advanced stages despite rigorous intervention, but in the majority, it spontaneously regresses before the threshold stage. Genetic factors, e.g. mutations in the Norrie disease (ND) gene, have been implicated in determining the progression of ROP to advanced stages. We have identified a novel C597A polymorphism of the ND gene; we screened this and another mutation in the ND gene, C110G, in 210 premature Kuwaiti infants using PCR-RFLP, DNA sequence analysis and DNA enzyme immunoassay hybridization to investigate their association with advanced-stage ROP. In this cohort of premature Kuwaiti newborns, 115 of 210 babies had no eye problems and served as controls, while 95 were found to have ROP. In 71 of the 95 ROP cases, the disease spontaneously regressed at or before stage 3, while in 24 of 95 ROP cases, the disease progressed to advanced stages 4 or 5. The incidence of the AA genotype of the C597A polymorphism was considerably higher in advanced-stage ROP cases (83.3%) compared to spontaneously regressing ROP cases (0%) and the normal controls (10.4%) (p < 0.0001). For the other genotypes, no significant difference was detected between the controls and ROP cases. In the case of the C110G mutation in the ND gene, no significant differences were detected between the controls and ROP cases, and the majority of subjects had a CC genotype in all three groups.

Effect of repeated doses of dexamethasone on the incidence and severity of respiratory distress syndrome in multifetal gestation between 24 and 34 weeks.

The objective of the study was to evaluate the effects of antenatal corticosteroid therapy in multiple pregnancy on the incidence and severity of respiratory distress syndrome (RDS). Twenty-two women with twin, 12 with triplet and 2 with quadruplet pregnancies and an emergency group of 20 mothers with twin pregnancies, who only had one course of dexamethasone, were compared with controls. Corticosteroid therapy was associated with a reduction in moderate to severe RDS in all groups (twins p < 0.01, triplets and quadruplets p < 0.008) and the emergency group with dexamethasone therapy (p < 0.036) when compared to their individual controls. Dexamethasone reduced the duration of stay in the neonatal intensive care unit of the emergency twin group (p < 0.01). Neonatal birth weights were significantly less in all groups treated with repeated doses in comparison to the controls.

Retinopathy of prematurity: mutations in the Norrie disease gene and the risk of progression to advanced stages.

BACKGROUND: Retinopathy of prematurity (ROP) is a retinal vascular disease that occurs in infants with short gestational age and low birth weight and may lead to retinal detachment and blindness. Missense mutations in the Norrie disease (ND) gene have been associated with the risk of progression to advanced stages in cases of ROP from the US and also in clinically similar ND and familial exudative vitreoretinopathy. METHODS: We have screened two ND gene mutations, namely A105T and Val60Glu, by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele-specific PCR methods, respectively, in 210 Kuwaiti premature newborns to replicate these findings in a different ethnic group. RESULTS: In the Kuwaiti premature newborn cohort, 115 of 210 babies had no eye problems and served as controls, while 95 were cases of ROP. In 71 of 95 ROP cases, the disease regressed spontaneously on or before stage 3, while in 24 of 95 ROP cases the disease progressed to advanced stages 4 and 5. In case of missense mutation (A105T), the AA genotype was detected in 96% of controls compared with 87% of ROP cases (NS); similarly no significant difference was found between spontaneously regressed ROP cases and those who progressed to advanced stages. For the Val60Glu mutation, no significant association was detected between the genotype and progression of ROP to advanced stages. CONCLUSIONS: Unlike data from the US, our findings from a Kuwaiti cohort of ROP cases and controls suggest a lack of association between the two ND gene mutations (A105T and Val60Glu) and ROP and the risk of progression of the disease to advanced stages.

Glutaric aciduria type II: observations in seven patients with neonatal- and late-onset disease.

The clinical, biochemical, and neuroradiologic findings and clinical follow-up of seven patients with glutaric aciduria type II are reported. Three phenotypes of the disease are encountered: neonatal-onset form with congenital anomalies (two patients) or without congenital anomalies (three patients) and late-onset form (two patients). The neonatal-onset form presents as an overwhelming illness, with severe hypoglycemia and metabolic acidosis leading to rapid death. Frequently it is associated with perinatal energy deprivation, a neonate with low birth weight and prematurity. The late-onset form presents with intermittent episodes of vomiting, hypoglycemia, and acidosis especially after meals rich in fat and/or proteins. All parents are consanguineous and have a first- or second-degree relationship. Initially, in the two phenotypes with neonatal onset and during crisis in the late-onset phenotype, routine laboratory evaluation showed severe metabolic acidosis, with an increased anion gap, hypoglycemia without ketonuria, and disturbed liver function tests. In the majority of patients with neonatal-onset forms, the kidneys, liver, and at times the spleen are enlarged with an increased echogenic pattern; however, no hepatic or renal cysts are detected. Cardiomegaly is observed in most patients. The diagnosis can be easily and rapidly reached through tandem mass spectrometry study of the blood and can further be confirmed by gas chromatography/mass spectrometry analysis of the urine organic acids. In this report, the magnetic resonance imaging/computed tomography brain studies showed brain atrophy, white matter disease, and in one patient, fluid-filled cavities in the periventricular area and putamina. Fluorine-18-labeled 2-fluoro-2-deoxyglucose positron emission tomographic (FDG PET) brain studies in two patients with late-onset disease showed slightly decreased activity in the cerebral cortex in one and in the caudate nuclei in the other. Brain FDG PET scan and magnetic resonance spectroscopy were normal in one patient with neonatal-onset disease. All patients were treated with a diet low in fat and protein, oral riboflavin, and carnitine. The results were promising for the late-onset disease. Intravenous carnitine gave rewarding results in one patient with neonatal-onset disease.

Clinical, fluorine-18 labeled 2-fluoro-2-deoxyglucose positron emission tomography (FDG PET), MRI of the brain and biochemical observations in a patient with 4-hydroxybutyric aciduria; a progressive neurometabolic disease.

We report a five-year-old boy with 4-hydroxybutyric aciduria. The child presented with global developmental delay, severe hypotonia and myoclonic seizures. The urine 4-hydroxybutyric acid was 1038 times that of normal, and other organic acids related to its further metabolism were also increased. Electroencephalography showed findings indicative of cerebral dysfunction. However, other neurophysiological studies were normal. Clinical improvement was observed after the administration of vigabatrin and dextromethorphan. Magnetic resonance imaging of the brain revealed cerebellar vermin atrophy and subtle white matter changes in the cerebral hemispheres. Fluorine-18 labeled 2-fluoro-2-deoxyglucose positron emission tomographic (FDG PET) scan of the brain showed a marked decrease in the cerebellar metabolism, probably related to atrophy of cerebellar vermis and secondary cerebellar deafferentation. FDG PET scan is found to be of value in the understanding and assessment of brain functional alterations. It may be useful in monitoring and optimizing treatment strategies of this rare disease.

Clinical and cerebral FDG PET scan in a patient with Krabbe's disease.

A 2-year, 6-month-old Saudi male with infantile Krabbe's disease was studied with fluorine-18-labeled-2-fluoro-2-deoxyglucose positron emission tomography (FDG PET) scan. The patient presented with a gradual loss of developmental milestones, irritability, and crying. At the advanced stage of the disease, he developed tonic-clonic seizures and became a microcephalic, extremely irritable, blind, spastic quadriplegic child, with no deep tendon reflexes. Laboratory studies revealed normal blood chemistry, muscle enzymes, very long chain fatty acids, and acylcarnitines. No abnormal urinary organic acids were detected. The cerebrospinal fluid protein concentration was increased. Magnetic resonance imaging of the brain revealed mild brain atrophy and white matter disease mainly in the centrum semiovale. Electroretinography was normal; however, electroencephalography and visual-evoked potentials were abnormal. Peripheral nerve conduction studies documented a demyelinating neuropathic process. The FDG PET study of the brain demonstrated a marked decrease in the metabolism of the left cerebral cortex and no uptake in the caudate heads. Normal glucose uptake was observed in the thalami, lentiform nuclei, and cerebellum. The patient did not present for subsequent clinic visits and is presumed dead.

Missense mutations in norrie disease gene are not associated with advanced stages of retinopathy of prematurity in Kuwaiti arabs.

Retinopathy of prematurity (ROP) is a disease characterized by retinal neovascularization, possibly leading to retinal detachment and finally blindness. In a proportion of ROP cases, the disease progresses to advanced stages despite rigorous intervention. Missense mutations of the Norrie disease (ND) gene have been associated with progression of the disease in ROP cases from the USA. We have investigated the presence of ND gene mutations in 102 premature newborns of Kuwaiti Arab origin to replicate this finding in a different population/racial group. 56 (55%) of these newborns had normal eyes and served as controls. In 35 (34%) cases, the ROP regressed spontaneously during stage 1-3. In 11 (11%) cases, ROP progressed to advanced stages. A PCR-RFLP method was used to detect the mutations in exon 3 of the ND gene and confirmed the DNA sequence by direct sequencing of the PCR product. The [R121W] mutation of the ND gene was not detected in the premature newborns screened from our Kuwaiti population/group. For the second mutation [L108P], a genotype (PP) was present in 98% of the premature newborns screened and only in 1 of 56 normal infants was the (LL) genotype detected. Our population is genetically homogenous in that genotype (PP) was detected at codon 108 in almost all controls and ROP cases. We did not find an association between the presence or absence of missense mutations of the ND gene and the risk of severe ROP.

Threshold stage of retinopathy of prematurity: maternal and neonatal risk factors.

BACKGROUND: The aim of this study was to review the maternal and neonatal risk factors associated with retinopathy of prematurity (ROP) and the threshold stage of the disease. PATIENTS AND METHODS: In this prospective cohort study, all preterm infants of less than 1501 g birth weight were screened for ROP between January 1996 and December 1997 at the neonatal unit of the Maternity Hospital in Kuwait. The rate of the threshold stage of ROP, as well as risk factors associated with the disease, were identified. RESULTS: A total of 234 babies were screened for ROP, of which 151 (64.5%) developed the disease and 34 (14.5%) had the threshold stage of ROP. Several factors were found to be associated with ROP and threshold ROP. Stepwise regression analysis revealed that low birth weight (P<0.002) and exposure to high oxygen concentration (P<0.0001) were independently associated with ROP. In addition, low birth weight (P<0.006), high oxygen concentration (P<0.003), and culture-proven sepsis (P<0.04) were found to be independent predictors of threshold ROP. CONCLUSION: Apart from low birth weight and exposure to high oxygen therapy, which are well-documented risk factors of ROP, septicemia was also found to be associated with the threshold stage of ROP.

Retinopathy of prematurity in infants with birth weight above 1500 grams.

OBJECTIVE: To identify the rate and prognosis of retinopathy of prematurity (ROP) among newborn infants of birthweight of above 1500 grams, and the possible risk factors associated with the disease. DESIGN: A prospective cohort study. SETTING: Neonatal unit at Maternity Hospital, Kuwait city, Kuwait. METHODS: All low birth weight infants were examined for the presence of ROP in the period between January 1996 to December 1997. Prospective collection of data on babies who were above 1500 grams was done to find an association between the disease in these babies and some of the maternal and neonatal risk factors. RESULTS: A total of 68 babies of birth weight above 1500 grams were screened for ROP out of which 13 (19.1%) had different stages of the disease. None of the patients had threshold disease requiring surgery. Among the risk factors chosen, oxygen therapy, presence of hypotension at birth and the non-use of surfactant were the only risk factors to be associated with disease. However, with logistic regression analysis, none of these were independently associated with ROP. CONCLUSION: ROP may occur in newborn infants of larger birthweight but with good prognosis, and oxygen therapy seems to predispose to the disease.

X-linked adrenoleukodystrophy. The Saudi experience.

OBJECTIVES: To evaluate the clinical, biochemical, neuroradiological, and neurophysiological findings of patients with X-linked adrenoleukodystrophy. METHODS: Retrospective study evaluating the data of 10 X-linked adrenoleukodystrophy patients diagnosed at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. RESULTS: The common presenting symptoms were deterioration in school performance, vision and hearing, behavioral changes, and seizures. Eight patients survived 1-4 years and one patient 12 years after the initial presentation, while one patient expired. Six patients had the childhood form, 3 had the adolescent form and one had the adrenomyeloneuropathy form. Six are in an advanced stage of the disease and 3 have mild to moderate spasticity. All except 2 manifested moderate to severe dementia with variable degrees of visual loss. Decreased hearing and features of adrenal insufficiency were seen in 7 patients. Very long chain fatty acids were significantly increased in seven and mildly elevated in 2 patients, however the C26 to C22 ratio was increased in all. The characteristic high-signal intensity of parieto-occipital white matter on brain magnetic resonance imaging T2-weighted images was observed in all patients. Two patients had functional study of the brain, which showed hypometabolic activity in gray and white matter of the occipital lobes. Various neurophysiological abnormalities were detected. The response to different treatment modalities was not promising. CONCLUSION: The disease is more common than had been previously recognized due to phenotypic variability and a wide spectrum of presentations. This report describes various aspects of this disorder and emphasizes the importance of early identification and treatment of asymptomatic but biochemically affected individuals, since all current therapeutic approaches are disappointing if overt neurological abnormalities have been already developed.

X-linked adrenoleukodystrophy. The Saudi experience.

OBJECTIVE: To evaluate the clinical, biochemical, neuroradiological, and neurophysiological findings of patients with X-linked adrenoleukodystrophy. METHODS: Retrospective study evaluating the data of 10 X-linked adrenoleukodystrophy patients diagnosed at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. RESULTS: The common presenting symptoms were deterioration in school performance, vision and hearing, behavioral changes, and seizures. Eight patients survived 1-4 years and one patient 12 years after the initial presentation, while one patient expired. Six patients had the childhood form, 3 had the adolescent form and one had the adrenomyeloneuropathy form. Six are in an advanced stage of the disease and 3 have mild to moderate spasticity. All except 2 manifested moderate to severe dementia with variable degrees of visual loss. Decreased hearing and features of adrenal insufficiency were seen in 7 patients. Very long chain fatty acids were significantly increased in seven and mildly elevated in 2 patients, however the C26 to C22 ratio was increased in all. The characteristic high-signal intensity of parieto-occipital white matter on brain magnetic resonance imaging T2-weighted images was observed in all patients. Two patients had functional study of the brain, which showed hypometabolic activity in gray and white matter of the occipital lobes. Various neurophysiological abnormalities were detected. The response to different treatment modalities was not promising. CONCLUSION: The disease is more common than had been previously recognized due to phenotypic variability and a wide spectrum of presentations. This report describes various aspects of this disorder and emphasizes the importance of early identification and treatment of asymptomatic but biochemically affected individuals, since all current therapeutic approaches are disappointing if overt neurological abnormalities have been already developed.

Hyperpipecolic acidemia: clinical, biochemical, and radiologic observations.

Pipecolic acid is a biochemical marker frequently detected in group 1 peroxisomal disorders (peroxisomal biogenesis disorders). Its presence, in addition to the constellation of particular phenotypic manifestations and pathologic findings, has led to its recent classification under disorders of peroxisomal biogenesis as a separate disease entity (hyperpipecolic acidemia or hyperpipecolatemia). The clinical, biochemical, and radiologic findings observed in three patients diagnosed with hyperpipecolic acidemia are reported.

Cerebral fluorine-18 labeled 2-fluoro-2-deoxyglucose positron emission tomography (FDG PET), MRI, and clinical observations in a patient with infantile G(M1) gangliosidosis.

The clinical, biochemical, pathological and neuroradiological findings of a 2-year-old Saudi boy with infantile G(M1) gangliosidosis are reported. The patient had a progressive neurologic deterioration, manifesting with developmental regression, sensorimotor and psychointellectual dysfunction and generalized spasticity that started at 4 months of age. Cherry-red macula, facial dysmorphia, hepatomegaly, exaggerated startle response to sounds, skeletal dysplasia, and vacuolated foamy lymphocytes that contain finely fibrillar material in addition to lamellar membranes and electron-dense rounded bodies were seen. MRI of the brain demonstrated mild diffuse brain atrophy and features of delayed dysmyelination and demyelination. Brain FDG PET scan revealed a mild decrease in the basal ganglia uptake, and moderate to severe decrease in thalamic and visual cortex uptake, and an area of increased glucose uptake in the left frontal lobe, probably representing an active seizure focus. The functional changes indicated by FDG PET scan and the structural abnormalities shown on MRI were found to be complementary in the imaging evaluation of infantile G(M1) gangliosidosis.

Clinical, biochemical, and molecular characterization of patients with glutathione synthetase deficiency.

Pyroglutamic aciduria (5-oxoprolinuria) is a rare autosomal recessive disorder caused by either glutathione synthetase deficiency (GSSD) or 5-oxoprolinase deficiency. GSSD results in low glutathione levels in erythrocytes and may present with hemolytic anemia alone or together with pyroglutamic aciduria, metabolic acidosis, and CNS damage. Five patients with pyroglutamic aciduria were studied. All presented with hemolytic anemia and metabolic acidosis. Two (brothers) also had Fanconi nephropathy, which is not seen in pyroglutamic aciduria. Molecular analyses of the GSS gene was performed in 3 patients. RT-PCR and heteroduplex analysis identified a homozygous deletion in 1 patient and a homozygous mutation in 2 others (brothers with Fanconi nephropathy). Sequencing of glutathione synthetase (GSS) cDNA from the first patient showed a 141-bp deletion corresponding to the entire exon 4, whilst the corresponding genomic DNA showed a G491 --> A homozygous splice site mutation. Sequencing of GSS cDNA from the Fanconi nephropathy patients showed a C847 --> T [ARG283 --> CYS] mutation in exon 9.