INPP5E: Converts phosphatidylinositol 3,4,5-trisphosphate (PtdIns 3,4,5-P3) to PtdIns-P2. Specific for lipid substrates, inactive towards water soluble inositol phosphates. Defects in INPP5E are the cause of Joubert syndrome type 1 (JBTS1). A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease. Defects in INPP5E are the cause of mental retardation- truncal obesity-retinal dystrophy-micropenis (MORMS). An autosomal recessive disorder characterized by moderate mental retardation, truncal obesity, congenital non-progressive retinal dystrophy, and micropenis in males. The phenotype is similar to Bardet-Biedl syndrome and Cohen syndrome Distinguishing features are the age of onset, the non-progressive nature of the visual impairment, lack of dysmorphic facies, skin or gingival infection, microcephaly, mottled retina, polydactyly, and testicular anomalies. Belongs to the inositol 1,4,5-trisphosphate 5- phosphatase type IV family. 2 isoforms of the human protein are produced by alternative splicing.
Protein type: Phosphatase (non-protein); Carbohydrate Metabolism - inositol phosphate; EC 3.1.3.36
Chromosomal Location of Human Ortholog: 9q34.3
Cellular Component: ruffle; cytoskeleton; plasma membrane; axoneme; cytosol
Molecular Function: phosphoinositide 5-phosphatase activity; inositol-polyphosphate 5-phosphatase activity
Biological Process: phospholipid metabolic process; organelle organization and biogenesis; inositol phosphate dephosphorylation; phosphatidylinositol biosynthetic process; phosphoinositide dephosphorylation
Disease: Mental Retardation, Truncal Obesity, Retinal Dystrophy, And Micropenis Syndrome; Joubert Syndrome 1
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