THG1L-related disorder is associated with a spectrum of features:
• Developmental delays
• Cerebellar hypoplasia
• Ataxia
• Nystagmus
• Dysarthria
• Hypotonia
• Microcephaly
• Intractable epilepsy
• Laryngomalacia
• Congenital heart defects*
• Haematological abnormalities*
• Inguinal hernia*
• Intrauterine growth restriction
*Symptom only reported in one individual
Homozygosity of the p.(Val55Ala) variant has been reported with mild and slowly progress or non-progressive features. These features include mild motor developmental delays, ataxia, cerebellar vermis hypoplasia, and near normal/ normal intelligence.
Individuals compound heterozygous for the p.(Val55Ala) variant and another variant have been reported to have a more severe phenotype.
THG1L