Confirmation of the assignment of the Sanjad-Sakati (congenital hypoparathyroidism) syndrome (OMIM 241410) locus to chromosome lq42-43.
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Biomedical subjects
Publications and source records attributed to N A Sakati.
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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.
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OBJECTIVE: To describe two patients with Fanconi's nephropathy secondary to glycogen storage disease and speculate on the possible etiology. DESIGN: Convenience sample. SETTING: Tertiary care, referral center. PATIENTS: Two related children referred for failure to thrive, rickets, and hepatomegaly. INTERVENTION: Dietary and therapeutic measures for rickets and renal tubular acidosis. MEASUREMENTS AND RESULTS: The main laboratory findings were fasting hypoglycemia and massive glucosuria, with evidence of multiple renal tubular dysfunction characteristic of the Fanconi syndrome. Liver and kidney biopsy specimens were consistent with glycogen storage disease. Enzymatic assay of liver homogenates revealed marked deficiency of phosphorylase b kinase in one patient and absent activity in the other. CONCLUSION: Phosphorylase b kinase deficiency may be causally related to hepatorenal glycogenosis with the Fanconi syndrome. More patients with this syndrome need to be studied before a definitive causal role is implicated.
UNLABELLED: OBJECTIVE, PATIENTS AND DESIGN: X-linked hypophosphataemic rickets (HYP) is the most common inherited form of rickets and the gene causing this disorder has been localized to Xp22.3-p21.3 by linkage studies of affected families of Northern European origin. In addition, the locus order Xpter-(DXS207-DXS43,DXS197)-HYP-DXS41-X cen has been established and the flanking markers are useful for the presymptomatic diagnosis of HYP. However, a recent study indicates locus heterogeneity and this may hinder the use of the flanking markers for presymptomatic diagnosis in additional families and in particular those from different populations. We have therefore investigated one Saudi-Arabian family (13 affected and six unaffected members) with hypophosphataemic rickets for linkage to these and other X-linked markers. A total of 17 cloned human X chromosome sequences identifying restriction fragment length polymorphisms were used to localize the mutant gene causing this disorder in the Saudi Arabian family. RESULTS: Nine (four from Xp and five from Xq) of the 17 X-linked DNA probes proved informative and linkage was established between HYP and the DSX41 locus, peak LOD score = 4.22 (recombination fraction, theta = 0.00). A positive peak LOD score of 2.32 (theta = 0.05) was also obtained between HYP and the DXS207 locus. Thus, the HYP gene in this Saudi Arabian family is linked to two of the four flanking markers which demonstrated linkage in families of Northern European origin. CONCLUSION: We conclude that the X-linked hypophosphataemic rickets gene in a Saudi Arabian family is located in the Xp22.3-p21.3, a region where this gene has previously been mapped by linkage studies of families of Northern European origin. Our studies have not demonstrated locus heterogeneity, so the flanking markers for HYP previously established in the families of Northern-European origin will be useful in the genetic counselling and presymptomatic diagnosis of this disorder in the Saudi Arabian family.
Twelve infants (six boys, six girls) with severe hypocalcaemic tetany or convulsions were seen over a three year period. Nine patients were symptomatic in the newborn period. Their hypocalcaemia was associated with hyperphosphataemia and very low concentrations of immunoreactive parathyroid hormone. None of the babies suffered from congenital cardiac disease. Cell mediated immunity, measured in five patients, was normal. There were no chromosomal abnormalities but all patients shared several dysmorphic features including deep set eyes, microcephaly, thin lips, beaked nose tip, external ear anomalies, micrognathia, and depressed nasal bridge. Mental retardation of varying degree was found in all patients. All had severe intrauterine and postnatal growth retardation. Four patients have died. The remaining eight patients are on treatments with vitamin D and calcium supplements with no change in their growth pattern. We believe that this association of congenital hypoparathyroidism with severe growth failure and dysmorphism represents a new syndrome.
Robinow syndrome and Crigler-Najar syndrome were encountered in 2 Saudi offspring of first cousins. Both died at age 4 months. The parents lost 2 previous children at age 2 months with progressive jaundice but without fetal facial characteristics.
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Three affected children (a 13-year-old girl and her 7- and 8-year-old brothers) in a sibship of eight had findings consistent with the Saldino-Mainzer syndrome (skeletal dysplasia associated with Leber's congenital amaurosis, familial juvenile nephronophthisis, and cone-shaped epiphyses of the hands). Two also had pigmented midline nevi. Although tapetoretinal degeneration and familial juvenile nephronophthisis are associated in the inherited Senior-Loken syndrome, the rare association of these abnormalities with cone-shaped epiphyses of the hands suggested an autosomal recessive syndrome with variable expression remarkably similar to the Saldino-Mainzer syndrome, which may or may not be distinct from the Senior-Loken syndrome. The association of tapetoretinal degeneration with skeletal dysplasia may indicate asymptomatic renal or hepatic disease.
A distinct and previously undescribed syndrome has been observed in six Saudi Arabian patients from two highly inbred families. The parents were normal, indicating an autosomal recessive pattern of inheritance. All the patients have a distinctive facial appearance, hypogonadism, sparse or absent hair, diabetes mellitus, mental retardation, mild deafness, and variable S-T and T wave abnormalities on the electrocardiograph.
A Samoan patient and a Saudi-Arabian patient were found to have abnormalities in the pattern of organic acid metabolites characteristic of 3-methylcrotonylglycinuria, propionic acidaemia and lactic acidosis. Both patients died early in life. The metabolic pattern is diagnostic of multiple carboxylase deficiency and an enzymatic diagnosis was made in a subsequent affected sibling of the first patient. Deficiency of the three carboxylases suggests a primary defect in the metabolism of biotin which is required for their activity. The importance of the recognition of the clinical picture is highlighted by the fact that this lethal disease is readily treated with biotin. These patients have prominent skin lesions which can serve as alerting signs for the diagnosis.
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An infant with aplastic alae nasi, imperforate anus, focal aplasia cutis over the fontanels, microcephaly, and mental retardation is presented as an example of the Johanson-Blizzard syndrome. The infant failed to thrive and had evidence of malabsorption. He died at 4 months of age. The occurrence of extensive consanguinity in his family and the occurrence of two other members of the kindred with a similar syndrome indicate that this disorder is transmitted by an autosomal recessive gene.