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Condition report · Neurological

TRAPPC9-Related Intellectual Disability

A rare neurodevelopmental disorder causing intellectual disability, a small head size and often obesity. It is caused by changes in both copies of the TRAPPC9 gene.

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The condition we analyse

Autosomal recessive

Caused by loss of function of both copies of TRAPPC9, a gene involved in transport within cells. Some reported families are consanguineous.

Signs and symptoms

Intellectual disability with marked speech delay, a small head size (microcephaly) and obesity are common. Brain MRI can show structural abnormalities, such as cerebral and cerebellar hypoplasia, and there may be dysmorphic facial features. Behavioural differences, such as outbursts, have also been reported.

What a diagnosis changes

Developmental, speech and educational support, with attention to weight and diet and treatment of seizures if present. Carrier testing of relatives and genetic counselling are available.

Genes analysed

Also known as

autosomal recessive intellectual disability due to TRAPPC9 deficiency

MONDO:0018123Orphanet 352530MedGen 1644787Sources: [1][2][3]

References

  1. Radenkovic S, Martinelli D, Zhang Y, Preston GJ, Maiorana A, Terracciano A et al., 2022. TRAPPC9-CDG: A novel congenital disorder of glycosylation with dysmorphic features and intellectual disability. Genetics in medicine : official journal of the American College of Medical Genetics
  2. Uctepe E, Yesilyurt A, Esen FN, Tumer S, Mancilar H, Sonmez FM, 2024. TRAPPC9-Related Intellectual Disability: Report of Two New Cases and Review of the Literature. Molecular syndromology
  3. Wilton KM, Gunderson LB, Hasadsri L, Wood CP, Schimmenti LA, 2021. Profound intellectual disability caused by homozygous TRAPPC9 pathogenic variant in a man from Malta. Molecular genetics & genomic medicine

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