Study in Healthy Subjects, Patients With Urea Cycle Disorders (UCD) and Carriers of UCD Mutations to Evaluate Urea Cycle Function

Cytonet

Status

Completed

Conditions

Urea Cycle Disorders

Treatments

Other: oral administration of Sodium [1,2-13C]-Acetate

Study type

Interventional

Funder types

Industry

Other

Identifiers

NCT01549015

CCD09

2011-002472-16 (EudraCT Number)

Details and patient eligibility

About

This diagnostic study will be performed to investigate the performance of the urea cycle in healthy subjects, asymptomatic carriers of Urea Cycle Disorders (UCD) mutations and subjects with genetically proven urea cycle disorders. The ureagenesis rate will be measured by 13C incorporation assay, a method for in vivo measurement of urea cycle performance with stable isotopes.

Full description

In this diagnostic study CCD09, the urea metabolism in UCD subjects (patients and carriers) and healthy subjects of different age and sex will be assessed by measurement of the incorporation of 13C from orally taken sodium [1,2-13C]-acetate into urea by 13C stable isotope ratio detection. The aim of the study is to determine the 13C urea production and to quantify the total urea production in healthy subject, gene defect carrier or patient as marker for the functioning of the urea cycle. Since there are still only few data available using this specific method for measurement of urea cycle performance, the aim of this study CCD09 is to gain additional results on the 13C assay. To this end, comparison will be made between 13C urea production observed in healthy subjects, UCD patients, and asymptomatic mutation carriers.

An evaluation of this study may also enable the treating physician to better judge the severity of disease and the future risk of metabolic decompensations in patients as well as the potential risk for so far asymptomatic carriers.

Enrollment

37 patients

Sex

All

Ages

Under 65 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

All study groups:

• Written informed consent given by subjects or his/her parents/legal guardians who are able to understand and follow instructions related to the study

Group 1 Healthy Volunteers:

Age: 18 - 65 years
Healthy subjects
No clinical or laboratory parameter outside normal ranges at screening and judged as clinically relevant by the investigator

Group 2 Symptomatic UCD patients with genetically confirmed CPSD, OTCD, ASSD, or ASLD:

Age: 0 - 65 years

Symptomatic subjects with genetically confirmed Carbamylphosphate synthetase I Deficiency [CPSD], Ornithine Transcarbamylase Deficiency [OTCD], Argininosuccinate Synthetase Deficiency [Citrullinaemia type I], Argininosuccinate Lyase Deficiency [ASLD]
at least 1 metabolic decompensation with clinical signs of hyperammonemia in medical history or genetically confirmed and prospectively treated siblings of symptomatic patients, even without clinical symptoms
Confirmed diagnosis and medical history available (in particular number and severity of metabolic crises)

Group 3 Asymptomatic carriers of UCD mutations:

Age: 0 - 65 years
Asymptomatic carriers of mutations for Carbamylphosphate synthetase I Deficiency [CPSD], Ornithine Transcarbamylase Deficiency [OTCD], Argininosuccinate Synthetase Deficiency [Citrullinaemia type 1], Argininosuccinate Lyase Deficiency [ASLD] no dietary protein restriction, no intake of ammonia scavenging drugs, no known metabolic decompensation with clinical signs of hyperammonemia

Group 4:

Infants between 8 - 10 kg body weight Symptomatic subjects with genetically confirmed Carbamylphosphate synthetase I Deficiency [CPSD] Ornithine Transcarbamylase Deficiency [OTCD] Argininosuccinate Synthetase Deficiency [Citrullinaemia type I] Argininosuccinate Lyase Deficiency [ASLD] at least 1 metabolic decompensation with clinical signs of hyperammonemia in medical history or genetically confirmed and prospectively treated siblings of symptomatic patients, even without clinical symptoms
Confirmed diagnosis and medical history available (in particular number and severity of metabolic crises

Exclusion criteria

Acute illness, including vomiting, fever or other sign of infection
Participation in other invasive clinical trials within 30 days prior to inclusion
Liver or renal disease
Acute seizures
Coma
Bleeding disorder
Blood ammonia > 100 µmol/l for patients with a urea cycle disorder and blood ammonia > normal for healthy probands and asymptomatic carriers
Metabolic acidosis
Pregnancy or lactation
Body weight < 8kg
Chronic somatic or psychiatric disease not related to UCD