TY - JOUR T1 - Phosphoserine phosphatase deficiency in a patient with Williams syndrome. JF - Journal of Medical Genetics JO - J Med Genet SP - 594 LP - 596 DO - 10.1136/jmg.34.7.594 VL - 34 IS - 7 AU - J Jaeken AU - M Detheux AU - J P Fryns AU - J F Collet AU - P Alliet AU - E Van Schaftingen Y1 - 1997/07/01 UR - http://jmg.bmj.com/content/34/7/594.abstract N2 - Decreased serine levels were found in plasma and cerebrospinal fluid (CSF) of a boy with pre- and postnatal growth retardation, moderate psychomotor retardation, and facial dysmorphism suggestive of Williams syndrome. Fluorescence in situ hybridisation with an elastin gene probe indicated the presence of a submicroscopic 7q11.23 deletion, confirming this diagnosis. Further investigation showed that the phosphoserine phosphatase (EC 3.1.3.3.) activity in lymphoblasts and fibroblasts amounted to about 25% of normal values. Oral serine normalised the plasma and CSF levels of this amino acid and seemed to have some clinical effect. These data suggest that the elastin gene and the phosphoserine phosphatase gene might be closely linked. This seems to be the first report of phosphoserine phosphatase deficiency. ER -