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The hyperornithinemia–hyperammonemia-homocitrullinuria syndrome

Overview of attention for article published in Orphanet Journal of Rare Diseases, March 2015
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Title
The hyperornithinemia–hyperammonemia-homocitrullinuria syndrome
Published in
Orphanet Journal of Rare Diseases, March 2015
DOI 10.1186/s13023-015-0242-9
Pubmed ID
Authors

Diego Martinelli, Daria Diodato, Emanuela Ponzi, Magnus Monné, Sara Boenzi, Enrico Bertini, Giuseppe Fiermonte, Carlo Dionisi-Vici

Abstract

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a rare autosomal recessive disorder of the urea cycle. HHH has a panethnic distribution, with a major prevalence in Canada, Italy and Japan. Acute clinical signs include intermittent episodes of vomiting, confusion or coma and hepatitis-like attacks. Alternatively, patients show a chronic course with aversion for protein rich foods, developmental delay/intellectual disability, myoclonic seizures, ataxia and pyramidal dysfunction. HHH syndrome is caused by impaired ornithine transport across the inner mitochondrial membrane due to mutations in SLC25A15 gene, which encodes for the mitochondrial ornithine carrier ORC1. The diagnosis relies on clinical signs and the peculiar metabolic triad of hyperammonemia, hyperornithinemia, and urinary excretion of homocitrulline. HHH syndrome enters in the differential diagnosis with other inherited or acquired conditions presenting with hyperammonemia. A systematic review of publications reporting patients with HHH syndrome was performed. We retrospectively evaluated the clinical, biochemical and genetic profile of 111 HHH syndrome patients, 109 reported in 61 published articles, and two unpublished cases. Lethargy and coma are frequent at disease onset, whereas pyramidal dysfunction and cognitive/behavioural abnormalities represent the most common clinical features in late-onset cases or during the disease course. Two common mutations, F188del and R179* account respectively for about 30% and 15% of patients with the HHH syndrome. Interestingly, the majority of mutations are located in residues that have side chains protruding into the internal pore of ORC1, suggesting their possible interference with substrate translocation. Acute and chronic management consists in the control of hyperammonemia with protein-restricted diet supplemented with citrulline/arginine and ammonia scavengers. Prognosis of HHH syndrome is variable, ranging from a severe course with disabling manifestations to milder variants compatible with an almost normal life. This paper provides detailed information on the clinical, metabolic and genetic profiles of all HHH syndrome patients published to date. The clinical phenotype is extremely variable and its severity does not correlate with the genotype or with recorded ammonium/ornithine plasma levels. Early intervention allows almost normal life span but the prognosis is variable, suggesting the need for a better understanding of the still unsolved pathophysiology of the disease.

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Mendeley readers

Mendeley readers

The data shown below were compiled from readership statistics for 110 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 110 100%

Demographic breakdown

Readers by professional status Count As %
Student > Bachelor 20 18%
Student > Ph. D. Student 12 11%
Student > Master 12 11%
Researcher 11 10%
Student > Doctoral Student 6 5%
Other 18 16%
Unknown 31 28%
Readers by discipline Count As %
Medicine and Dentistry 31 28%
Biochemistry, Genetics and Molecular Biology 13 12%
Nursing and Health Professions 7 6%
Agricultural and Biological Sciences 5 5%
Psychology 5 5%
Other 15 14%
Unknown 34 31%
Attention Score in Context

Attention Score in Context

This research output has an Altmetric Attention Score of 4. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 22 May 2018.
All research outputs
#7,144,432
of 22,794,367 outputs
Outputs from Orphanet Journal of Rare Diseases
#1,024
of 2,615 outputs
Outputs of similar age
#83,388
of 259,193 outputs
Outputs of similar age from Orphanet Journal of Rare Diseases
#20
of 31 outputs
Altmetric has tracked 22,794,367 research outputs across all sources so far. This one has received more attention than most of these and is in the 68th percentile.
So far Altmetric has tracked 2,615 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 7.5. This one has gotten more attention than average, scoring higher than 60% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 259,193 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 67% of its contemporaries.
We're also able to compare this research output to 31 others from the same source and published within six weeks on either side of this one. This one is in the 35th percentile – i.e., 35% of its contemporaries scored the same or lower than it.