HHH syndrome

Classification according to ICD-10
E72.4	Ornithine metabolism disorders
ICD-10 online (WHO version 2019)

The HHH syndrome (Triple H syndrome) is an occurring in people very rare congenital , the ornithine of respective metabolic defect with the eponymous main features H yperornithinämie (increase in ornithine levels in blood plasma ), H yperammonämie , H omocitrullinurie (increase homocitrulline in the urine ).

Synonyms are: ORNT1 deficiency; Ornithine translocase deficiency; Ornithine transporter deficiency

The first description comes from the year 1969 by the American doctor Vivian E. Shih and colleagues.

The disease is not to be confused with the H syndrome .

distribution

So far, about 20 people have been reported to be affected; inheritance is autosomal - recessive .

root cause

The disease are mutations in SLC25A15 - gene on chromosome 13 locus q14.11 based encoding ornithine aminotransferase ( mitochondrial ornithine transporter ).

Clinical manifestations

Clinical criteria are:

• The onset of the disease varies in newborns, children and adults
• repeated episodes of lethargy , seizures , coma due to hyperammonaemia
• Mental retardation
• Muscle hypotension , ataxia , symptoms of paralysis

diagnosis

In addition to the laboratory changes that give it its name, the disturbed transport of ornithine into the mitochondria can be detected and confirms the diagnosis, possibly prenatally . This test is also suitable for prenatal diagnosis.

Differential diagnosis

A distinction must be made between carbamoyl phosphate synthetase deficiency and ornithine transcarbamylase deficiency .

therapy

Treatment consists of a low-protein diet with additional intake of arginine and citrulline .

literature

• SK Qadri, TW Ting, JS Lim, SS Jamuar: Milder Form of Urea Cycle Defect Revisited: Report and Review of Hyperornithinaemia-Hyperammonaemia-Homocitrullinuria (HHH) Syndrome Diagnosed in a Teenage Girl Presenting with Recurrent Encephalopathy. In: Annals of the Academy of Medicine, Singapore. Volume 45, No. 12, December 2016, pp. 563-566, PMID 28062886 (review).
• A. Zanatta, CM Viegas, FH Hickmann, W. de Oliveira Monteiro, A. Sitta, D. de Moura Coelho, CR Vargas, G. Leipnitz, M. Wajner: Ornithine In Vivo Administration Disrupts Redox Homeostasis and Decreases Synaptic Na (+ ), K (+) - ATPase Activity in Cerebellum of Adolescent Rats: Implications for the Pathogenesis of Hyperornithinemia-Hyperammonemia-Homocitrullinuria (HHH) Syndrome. In: Cellular and molecular neurobiology. Volume 35, No. 6, August 2015, pp. 797-806, doi: 10.1007 / s10571-015-0173-y , PMID 25772141 .
• L. Smith, MA Lambert, P. Brochu, G. Jasmin, IA Qureshi, EG Seidman: Hyperornithinemia, hyperammonemia, homocitrullinuria (HHH) syndrome: presentation as acute liver disease with coagulopathy. In: Journal of Pediatric Gastroenterology and Nutrition . Vol 15, No. 4, November 1992, pp. 431-436, PMID 1469525 (review).

Web links

• Genetics Home Reference

Individual evidence

1. ↑ ^{a b c d} Bernfried Leiber (founder): The clinical syndromes. Syndromes, sequences and symptom complexes . Ed .: G. Burg, J. Kunze, D. Pongratz, PG Scheurlen, A. Schinzel, J. Spranger. 7., completely reworked. Edition. tape 2 : symptoms . Urban & Schwarzenberg, Munich et al. 1990, ISBN 3-541-01727-9 .
2. ↑ ^{a b c d} Hyperornithinaemia-Hyperammonaemia-Homocitrullinaemia Syndrome. In: Orphanet (Rare Disease Database).
3. ^ VE Shih, ML Efron, HW Moser: Hyperornithinemia, hyperammonemia, and homocitrullinuria. A new disorder of amino acid metabolism associated with myoclonic seizures and mental retardation. In: American journal of diseases of children , Volume 117, No. 1, January 1969, pp. 83-92, PMID 5782534 .
4. ↑ Hyperornithinemia-hyperammonemia-homocitrullinemia syndrome.  In: Online Mendelian Inheritance in Man . (English)

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !