Pontocerebellar hypoplasia due to bi-allelic variants in MINPP1.

Abstract

Pontocerebellar hypoplasia (PCH) describes a group of rare heterogeneous neurodegenerative diseases with prenatal onset. Here we describe eight children with PCH from four unrelated families harboring the homozygous MINPP1 (NM_004897.4) variants; c.75_94del, p.(Leu27Argfs*39), c.851 C > A, p.(Ala284Asp), c.1210 C > T, p.(Arg404*), and c.992 T > G, p.(Ile331Ser). The homozygous p.(Leu27Argfs*39) change is predicted to result in a complete absence of MINPP1. The p.(Arg404*) would likely lead to a nonsense mediated decay, or alternatively, a loss of several secondary structure elements impairing protein folding. The missense p.(Ala284Asp) affects a buried, hydrophobic residue within the globular domain. The introduction of aspartic acid is energetically highly unfavorable and therefore predicted to cause a significant reduction in protein stability. The missense p.(Ile331Ser) affects the tight hydrophobic interactions of the isoleucine by the disruption of the polar side chain of serine, destabilizing the structure of MINPP1. The overlap of the above-mentioned genotypes and phenotypes is highly improbable by chance. MINPP1 is the only enzyme that hydrolyses inositol phosphates in the endoplasmic reticulum lumen and several studies support its role in stress induced apoptosis. The pathomechanism explaining the disease mechanism remains unknown, however several others genes of the inositol phosphatase metabolism (e.g., INPP5K, FIG4, INPP5E, ITPR1) are correlated with phenotypes of neurodevelopmental disorders. Taken together, we present MINPP1 as a novel autosomal recessive pontocerebellar hypoplasia gene.

• Authors: Bart Appelhof, Matias Wagner, Julia Hoefele, Anja Heinze, Timo Roser, Margarete Koch-Hogrebe, Stefan D Roosendaal, Mohammadreza Dehghani, Mohammad Yahya Vahidi Mehrjardi, Erin Torti, Henry Houlden, Reza Maroofian, Farrah Rajabi, Heinrich Sticht, Frank Baas, Dagmar Wieczorek, Rami Abou Jamra
• Journal: European journal of human genetics : EJHG (Eur J Hum Genet) Vol. 29 Issue 3 Pg. 411-421 (03 2021) ISSN: 1476-5438 [Electronic] England
• PMID: 33168985 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Codon, Nonsense
• Phosphoric Monoester Hydrolases
• multiple inositol-polyphosphate phosphatase

Topics

• Alleles
• Cerebellar Diseases (genetics, pathology)
• Child
• Child, Preschool
• Codon, Nonsense
• Female
• Homozygote
• Humans
• Infant
• Male
• Mutation, Missense
• Phosphoric Monoester Hydrolases (genetics)
• Protein Folding