Severe microcephalyGene: TNPO2
Comment on list classification: There are sufficient unrelated cases presenting were a relevant phenotype associated with variants in this gene to rate as Green at the next GMS panel update.
Created: 23 Sep 2021, 10:04 a.m. | Last Modified: 23 Sep 2021, 10:04 a.m.
Panel Version: 2.250
Goodman et al., 2021 (PMID: 34314705) reported on 15 unrelated individuals with different variants in this gene (14 de novo, 1 mosaic in mother; 12 SNVs, 3 in-frame deletions, 1 deletion-insertion). All had GDD and all those who were assessed also had ID (9/9), ranging from mild to severe. ID also suspected but not investigated in another 3 cases. 6 had seizures starting between 1 and 2.5 years of age. 5 individuals had microcephaly (HC ranging -2.77 to -4.53 SD). Other less common features were also observed such as variable brain, gastrointestinal and ophthalmologic abnormalities.
Notably 6 individuals had additional SNVs/CNVs of uncertain significance, some of which include known ID genes (e.g. SETBP1, CUX2, ARMC9, PDE4D), but were discounted due to lack of explanation of the overall patient phenotype.
Some functional studies conducted in Drosophila demonstrated that patient-associated variants caused neurodevelopmental defects that were dosage and location (of variant within protein) dependent.
Created: 23 Sep 2021, 10:03 a.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability; Dysmorphic features; Microcephaly; Seizures; Hypotonia
Gene: tnpo2 has been classified as Amber List (Moderate Evidence).
gene: TNPO2 was added gene: TNPO2 was added to Severe microcephaly. Sources: Literature Q3_21_rating tags were added to gene: TNPO2. Mode of inheritance for gene: TNPO2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: TNPO2 were set to 34314705 Phenotypes for gene: TNPO2 were set to Intellectual disability; Dysmorphic features; Microcephaly; Seizures; Hypotonia Review for gene: TNPO2 was set to GREEN