TG and TSHR mutations are the most common genetic defects in Saudi patients with CH. The prevalence of other disease-causing mutations is low, reflecting the consanguineous nature of the population. SLC26A7 mutations appear to be associated with thyroid dyshormonogenesis.

BackgroundHereditary hypophosphatemia is a group of rare renal phosphate wasting disorders. The diagnosis is based on clinical, radiological, and biochemical features, and may require genetic testing to be confirmed.MethodologyClinical features and mutation spectrum were investigated in patients with hereditary hypophosphatemia. Genomic DNA of 23 patients from 15 unrelated families were screened sequentially by PCR-sequencing analysis for mutations in the following genes: PHEX, FGF23, DMP1, ENPP1, CLCN5, SLC34A3 and SLC34A1. CytoScan HD Array was used to identify large deletions.ResultsGenetic evaluation resulted in the identification of an additional asymptomatic but intermittent hypophosphatemic subject. Mutations were detected in 21 patients and an asymptomatic sibling from 13 families (86.6%, 13/15). PHEX mutations were identified in 20 patients from 12 families. Six of them were novel mutations present in 9 patients: c.983_987dupCTACC, c.1586+2T>G, c.1206delA, c.436+1G>T, c.1217G>T, and g.22,215,887–22,395,767del (179880 bp deletion including exon 16–22 and ZNF645). Six previously reported mutations were found in 11 patients. Among 12 different PHEX mutations, 6 were de novo mutations. Patients with de novo PHEX mutations often had delayed diagnosis and significantly shorter in height than those who had inherited PHEX mutations. Novel compound heterozygous mutations in SLC34A3 were found in one patient and his asymptomatic sister: c.1335+2T>A and c.1639_1652del14. No mutation was detected in two families.ConclusionsThis is the largest familial study on Turkish patients with hereditary hypophosphatemia. PHEX mutations, including various novel and de novo variants, are the most common genetic defect. More attention should be paid to hypophosphatemia by clinicians since some cases remain undiagnosed both during childhood and adulthood.

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Serum Tamm-Horsfall protein (THP) levels were measured in 157 infants and children, 46 cord blood samples and 75 adults using an enzyme-linked immunosorbent assay. THP levels increased significantly across the age groups, suggesting a positive relationship with age. There was a strong positive relationship between serum THP and estimated glomerular filtration rate among children with chronic renal failure.

A child presented with ischaemic episodes of his left leg from the age of 2 months. He was found to have raised anticardiolipin antibodies so was started on low dose aspirin. At a three year follow up he was asymptomatic with a normal anticardiolipin antibody level while taking aspirin daily, probably for life. (Arch Dis Child 1996;75:342-343) Keywords: antiphospholipid syndrome, acute limb ischaemia.The antiphospholipid syndrome was first described in 1983 by Hughes et al in patients with systemic lupus erythematosus (SLE) Examination revealed a well looking baby boy with weight and head circumference on the 50th centile and length on the 97th centile. His limbs were not mottled or cyanosed. His femoral pulses and four-limb blood pressure measurements were normal. The rest of the examination was entirely normal.Since these episodes sounded ischaemic rather than being associated with temperature or autonomic immaturity as commonly seen in babies, we undertook further studies. Ultrasonography excluded a pelvic mass, and neither immersion in cold water nor compressing his femoral vessels precipitated similar episodes. Doppler studies of the femoral arteries and veins, echocardiography, and electrocardiography were all normal. His blood count was normal except for a platelet count of 600 x 1 09/l. The erythrocyte sedimentation rate (ESR) was 3 mm/hour, there was a normal clotting screen, a negative autoimmune profile, and no anti-DNA antibodies were detected. IgG anticardiolipin antibody was raised at 14.9 AEU (the upper range of normal being 7), with normal levels of IgM anticardiolipin antibody. However, by this time the episodes had stopped so the significance of the raised IgG anticardiolipin was questioned. The test was repeated at 9 months of age when the IgG anticardiolipin had risen to 26.5 AEU. We therefore diagnosed antiphospholipid syndrome without an obvious precipitating cause.