raremaprare-disease reference indexOrphadata 2026-06-23 · HPO 2026-09-01
ORPHA:247525

Citrullinemia type I

Synonyms: ASS deficiency · Argininosuccinate synthase deficiency · Argininosuccinate synthetase deficiency · Argininosuccinic acid synthase deficiency · Argininosuccinic acid synthetase deficiency · CTLN1 · Citrullinemia type 1 · Classic citrullinemia

Type
Disease
Group
Disorder
Inheritance
Autosomal recessive
Age of onset
All ages
Status
active

Citrullinemia type I is a rare autosomal recessive urea cycle defect characterized biologically by hyperammonemia and clinically by progressive lethargy, poor feeding and vomiting in the neonatal form (Acute neonatal citrullinemia type I) and by variable hyperammonemia in the later-onset form (Adult-onset citrullinemia type I).

1

Names in Orphadata languages

12 of 12 languages
LangNameSynonyms
enCitrullinemia type IASS deficiency · Argininosuccinate synthase deficiency · Argininosuccinate synthetase deficiency · Argininosuccinic acid synthase deficiency · Argininosuccinic acid synthetase deficiency · CTLN1 · Citrullinemia type 1 · Classic citrullinemia
frCitrullinémie type ICTLN1 · Citrullinémie classique · Citrullinémie type 1 · Déficit en ASS · Déficit en synthase de l'acide argininosuccinique · Déficit en synthase de l'argininosuccinate · Déficit en synthétase de l'acide argininosuccinique · Déficit en synthétase de l'argininosuccinate
deZitrullinämie Typ 1ASS-Mangel · Argininosuccinat-Synthase-Mangel · CTLN1 · Citrullinämie Typ I · Klassische Zitrullinämie
esCitrulinemia tipo ICTLN1 · Citrulinemia clásica · Citrulinemia tipo 1 · Deficiencia de ASS · Deficiencia de argininosuccinato sintasa · Deficiencia de argininosuccinato sintetasa · Deficiencia de ácido argininosuccínico sintasa · Deficiencia de ácido argininosuccínico sintetasa
itCitrullinemia, tipo ICTLN1 · Citrullinemia classica · Citrullinemia, tipo 1 · Deficit di ASS · Deficit di acido argininosuccinico sintasi · Deficit di acido argininosuccinico sintetasi · Deficit di argininosuccinato sintasi · Deficit di argininosuccinato sintetasi
nlCitrullinemie type IASS-deficiëntie · CTLN1 · Citrullinemie type 1 · Deficiëntie van argininobarnsteenzuursynthase · Deficiëntie van argininobarnsteenzuursynthetase · Deficiëntie van argininosuccinaatsynthase · Deficiëntie van argininosuccinaatsynthetase · Klassieke citrullinemie
ptCitrulinémia, tipo I
plCitrulinemia typu ICitrulinemia klasyczna · Citrulinemia typu 1 · CTLN1 · Niedobór ASS · Niedobór syntazy argininobursztynianu · Niedobór syntazy kwasu argininobursztynowego · Niedobór syntetazy argininobursztynianu · Niedobór syntetazy kwasu argininobursztynowego
csCitrulinémie, typ IASS deficit · Deficit argininosukcinátsyntetázy · Deficit syntázy kyseliny argininjantarové · Deficit syntetházy kyseliny argininjantarové · CTLN1 · Citrulinémie, typ 1 · Klasická citrulinémie
ukЦитрулінемія, тип IДефіцит аргініносукцинатсинтази · Дефіцит аргініносукцинатсинтетази · Дефіцит синтази аргінінобурштинової кислоти · Дефіцит синтетази аргінінобурштинової кислоти · Дефіцит АСС · Цитрулінемія типу 1 · Класична цитрулінемія · CTLN1
zh瓜氨酸血症I型精氨酸代琥珀酸合成酶缺乏症
trSitrülinemi tip ICTLN1 · ASS eksikliği · Sitrülinemi tip 1 · Klasik sitrülinemi · Arjininosükkinat sentaz eksikliği · Arjininosükkinat sentetaz eksikliği · Arjininosüksinik asit sentaz eksikliği · Argininosüksinik asit sentetaz eksikliği

Definition in:

2

Cross-references

qualifier = Orphanet mapping relation
SourceCodeQualifierICD relationValidation
OMIM215700Evalidated
ICD-10E72.2NTBTattributedvalidated
ICD-115C50.A3NTBTindexvalidated
MONDO0008988Evalidated
UMLSC4721769Evalidated
GARD6114Evalidated
MedDRA10058298Evalidated

E exact · NTBT this ORPHAcode is narrower than the target · BTNT broader than the target · ND not decided.

3

Classification

Preferential parent (Orphanet linearisation):

Parents in the classifications (1):

Children (2):

4

Genes

0 direct · 2 via subtypes

Orphanet records no gene directly on this code.

Recorded by Orphanet on subtypes of this disorder:

GeneSubtypeAssociationStatusHGNCEnsemblOMIMLocusNameSource of validation
ASS1ORPHA:247546Acute neonatal citrullinemia type IDisease-causing germline mutation(s) (loss of function) inAssessedHGNC:758ENSG000001307076034709q34.11argininosuccinate synthase 120301631[PMID]
ASS1ORPHA:247573Late-onset citrullinemia type IDisease-causing germline mutation(s) (loss of function) inAssessedHGNC:758ENSG000001307076034709q34.11argininosuccinate synthase 120301631[PMID]
5

Prevalence and incidence

5 records
TypeClassValueAreaQualificationValidationSource
Point prevalence1-9 / 100 0002.4 / 100 000EuropeValue and classValidatedEuropean Medicines Agency 2012[OTHER]
Prevalence at birth1-9 / 100 0001.28 / 100 000AustriaValue and classValidated20938748[PMID]
Prevalence at birth1-9 / 100 0004.5 / 100 000Korea, Republic ofValue and classValidated15906713[PMID]
Prevalence at birth1-9 / 1 000 0000.84 / 100 000Taiwan, Province of ChinaValue and classValidated20567911[PMID]
Prevalence at birth1-9 / 100 0001.13 / 100 000United StatesValue and classNot yet validatedISBN:79130356[OTHER]_15906712[PMID]_ ORPHANET

Value is Orphadata's ValMoy: the mean estimate per 100 000 for prevalence and incidence, the number of cases or families for case reports.

6

HPO phenotypes

28 annotations · validated 2019-07-04
HPOTerm (as annotated by Orphanet)Diagnostic
Very frequent (99-80%)
HP:0011966Elevated plasma citrulline
HP:0001987Hyperammonemia
Frequent (79-30%)
HP:0001399Hepatic failure
Occasional (29-5%)
HP:0000707Abnormality of the nervous system
HP:0001508Failure to thrive
HP:0011968Feeding difficulties
HP:0002480Hepatic encephalopathy
HP:0006889Intellectual disability, borderline
HP:0002342Intellectual disability, moderate
HP:0001254Lethargy
HP:0001950Respiratory alkalosis
HP:0001250Seizure
HP:0001257Spasticity
HP:0002013Vomiting
Very rare (<4-1%)
HP:0011448Ankle clonus
HP:0001251Ataxia
HP:0001259Coma
HP:0002020Gastroesophageal reflux
HP:0002315Headache
HP:0001252Hypotonia
HP:0002516Increased intracranial pressure
HP:0001256Intellectual disability, mild
HP:0007185Loss of consciousness
HP:0002076Migraine
HP:0000575Scotoma
HP:0001350Slurred speech
HP:0002789Tachypnea
HP:0000473Torticollis

Run the differential on the 2 obligate / very frequent terms

Annotation source: 30534838[PMID]_29423830[PMID]_28132756[PMID]_30035404[PMID]_20301631[PMID]

7

Sources for this card