Prepair 500+
Gene: POLR3B
Age of onset is typically in early childhood but later-onset cases have also been reported.
Mild DD & ID. Mild-Mod mental retardation. Variable spasticity. Inter & Intrafamilial varability.
Common variant c.1568T>A (p.Val523Glu) is very mild; hom individuals were either asymptomatic or very mildly symptomatic in early childhood.
More than 10 families reported. Early childhood onset of cerebellar ataxia and mild intellectual disabilities associated with diffuse hypomyelination apparent on brain MRI. Variable features include oligodontia and/or hypogonadotropic hypogonadism.
DD/ID is a feature
Phenotype-genotype correlation: Missense, frameshift, premature truncation and splice variants have been reported for Leukodystrophy, while de novo heterozygous missense variants have been reported for demyelinating Charcot-Marie-Tooth disease type 1I, and do not overlap with the recessive variants so far (Djordjevic, et al., 2021).
Hypomyelinating leukodystrophy-8 (HLD8) is an autosomal recessive neurologic disorder characterized by early childhood onset of cerebellar ataxia and mild intellectual disabilities associated with diffuse hypomyelination apparent on brain MRI. Variable features include oligodontia and/or hypogonadotropic hypogonadism. There is considerable inter- and intrafamilial variability.Created: 16 Apr 2025, 4:42 p.m. | Last Modified: 16 Apr 2025, 4:42 p.m.
Panel Version: 1.1868
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism,MIM#614381
Publications
Mode of pathogenicity
Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Gene: polr3b has been classified as Green List (High Evidence).
Phenotypes for gene: POLR3B were changed from Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism, 614381 (3) to Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism,MIM#614381
Publications for gene: POLR3B were set to
gene: POLR3B was added gene: POLR3B was added to Prepair 500+. Sources: Mackenzie's Mission,Expert Review Green Mode of inheritance for gene: POLR3B was set to BIALLELIC, autosomal or pseudoautosomal Phenotypes for gene: POLR3B were set to Leukodystrophy, hypomyelinating, 8, with or without oligodontia and/or hypogonadotropic hypogonadism, 614381 (3)