Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Juvenile Huntington disease (JHD) is a rare clinical entity characterized by disease onset before the age of 21. JHD accounts for <10% of Huntington disease patients. Transmission of JHD is paternal in 80-90% of cases. Patients with JHD usually carry more than 60 CAG repeats within the HTT gene. We report here on a 23-month-old boy presenting with global developmental delay first noted at 18 months of age. Clinical examination showed truncal hypotonia, postural and intentional tremor, limb rigidity, and ataxia. Cerebral magnetic resonance imagery (MRI) showed reduced cerebellar volume. Six months later, his 47-year-old father was seen for a 4-year history of progressive dementia with severe behavioral disturbance and chorea. Cerebral MRI showed discrete global and caudate atrophy. DNA analysis revealed a very large and heterogeneous expansion (210-250 CAG) in the child and a 43 CAG expansion of the HTT gene in the father. This unusual case demonstrates that very early onset JHD due to large CAG expansions should be considered in cases of global developmental delay associated with reduced cerebellar volume, including cases without known HD family history.
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PMID:Juvenile Huntington disease in an 18-month-old boy revealed by global developmental delay and reduced cerebellar volume. 2141 77

We report compound heterozygous variants in HTT, the gene encoding huntingtin, in association with an autosomal recessive neurodevelopmental disorder. Three siblings presented with severe global developmental delay since birth, central hypotonia progressing to spastic quadraparesis, feeding difficulties, dystonia (2/3 sibs), prominent midline stereotypies (2/3), bruxism (1/3), high myopia (2/3), and epilepsy (1/3). Whole exome sequencing identified compound heterozygous variants in HTT that co-segregated in the three affected sibs and were absent in an unaffected sib. There were no additional variants in other genes that could account for the reported phenotype. Molecular analysis of HTT should be considered, not just for Huntington's disease, but also in children with a Rett-like syndrome who test negative for known Rett and Rett-like syndrome genes.
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PMID:A novel neurodevelopmental disorder associated with compound heterozygous variants in the huntingtin gene. 2783 62