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Glycosylation in Patients With Galactosaemia

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02218632
Recruitment Status : Completed
First Posted : August 18, 2014
Last Update Posted : August 18, 2014
Health Research Board, Ireland
Medical Research Charities Group Ireland
University College Dublin
Information provided by (Responsible Party):
Children's University Hospital, Ireland

Brief Summary:

Galactosaemia is an inherited condition caused by a lack of an enzyme (catalyst) which normally breaks down galactose (the sugar found in milk products). This affects 1:19,000 births annually in Ireland (the highest incidence worldwide) and is screened for by the National Newborn Screening Programme. When an affected infant is diagnosed, galactose is immediately restricted from the diet. This prevents often fatal liver disease and other immediate complications. However, despite early treatment the majority of affected patients go on to develop long-term complications such as intellectual impairment, neurological complications, speech difficulties and infertility in females. The underlying mechanisms for these complications are unclear. The investigators have shown in detailed biochemical and gene analysis studies that major abnormalities affecting the function of complex molecules in the body, particularly glycoproteins, (consisting of sugar chains attached to proteins) persist in treated individuals which may lead to disturbances of the body's intrinsic cellular machinery and relate to the complications seen.

In this research the investigators expand on from their earlier studies to see if they can identify biomarkers and parts of the galactose/glycosylation pathways which could be modified or changed with new treatments to improve outcomes for this condition (i.e., IgG N glycans).

In more detail, the investigators test the use of the most abundant glycoprotein in human plasma (IgG) as an improved clinical test for monitoring the galactose control needed in patients and also to see if some patients (including children aged 5-12 yrs) might have a better predicted outcome with moderate increases of galactose in the diet. The investigators believe that these studies greatly improve the understanding of Galactosaemia with a view to improving current treatment options and future outcomes.

Condition or disease Intervention/treatment Phase
Classical Galactosaemia Other: lactose-free diet Dietary Supplement: Temporary oral galactose supplements Not Applicable

Detailed Description:

Classical Galactosaemia is an inherited disorder of galactose metabolism caused by profound deficiency of galactose-1-phosphate uridyltransferase (GALT: EC 2.7.712). This results in a systemic accumulation of toxic galactose intermediates and a decrease in the level of UDP-galactose, a required sugar for glycosylation. Galactosaemia has a relatively high incidence in Ireland, (1:19,000 births) presenting a particular public health problem. The neonatal life-threatening phenotype (liver disease, coagulopathy and sepsis) is rescued by restriction of dietary galactose. However, outcomes of treatment are disappointing beyond the neonatal period (even after successful newborn screening, early treatment and long term compliance). The majority of Irish patients harbour the severe Q188R Galt mutation.

56.5% of Irish patients ≥ 6yrs have IQs ≤ 79; and 91.2% of Irish female patients ≥ 13yrs have Premature Ovarian Insufficiency (POI). Unfortunately, the basic pathophysiology of this condition remains enigmatic with limited treatment approaches.

In their earlier work, the investigators reported very considerable variation in patient outcomes, even among siblings. The investigators have proposed that these differences are determined by variation in galactose accessory pathways (beyond the GALT deficiency). This may result in variable galactose tolerance in patients with linked variation in glycosylation pathways which could allow for enhanced UDP-galactose bioavailability essential for glycosylation. In their previous and current work the investigators have identified ongoing dysregulation of glycoprotein formation and expression of genes involved in glycan biosynthesis and cell signalling pathways in treated Galactosaemia patients.

The present proposal, which builds on published previous work, enables the investigators to establish that Galactosaemia is a modifiable, multi-systemic glycosylation defect. The overall objectives of the work are to progress the development of biochemical markers (IgG N-glycan analysis) as prognostic indices for potentially modifiable relevant pathways. The investigators consider how the phenotype could be relaxed in some patients with Classical Galactosaemia, initially by studies of modification of exogenous galactose requirements to identify if the ongoing glycan processing defects identified may be improved reflecting accessory pathways of galactose disposal.

Study Aim: Expand previous and published work using IgG N-glycan analysis to examine the glycosylation status of treated adult Galactosaemia patients in a larger study and develop this test as a reliable diagnostic tool. The investigators also carry out a pilot study to examine the effects of diet relaxation in paediatric patients (5-12 yrs) aiming to determine optimum galactose intake levels for this cohort with the hope of preventing long-term complications later in life. The investigators propose that this research offers new insights into the ongoing pathophysiology of this rare disorder with the possibility of developing new treatment targets, which over time could be cost-effective by preventing major disability.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 26 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Galactosaemia, a Modifiable Multi-system Glycosylation Disorder?
Study Start Date : July 2012
Actual Primary Completion Date : August 2014
Actual Study Completion Date : August 2014

Arm Intervention/treatment
Active Comparator: lactose-free diet
lactose-free diet (standard therapy) vs. lactose-free diet plus temporary oral galactose supplements
Other: lactose-free diet
standard diet
Other Name: On established lactose-free diet

Active Comparator: lactose free diet
lactose-free diet (standard therapy)
Dietary Supplement: Temporary oral galactose supplements
galactose supplements in the range of physiological galactose production
Other Name: In addition to lactose-free diet

Primary Outcome Measures :
  1. Number of patients with Classical Galactosaemia on a lactose-free diet in Ireland with disease specific complications [ Time Frame: 2 years ]
    clinical monitoring and biochemical assessment to determine the number of patients with classical galactsaemia in Ireland with disease specific complications

Secondary Outcome Measures :
  1. Number of participants with Classical Galactosaemia with variations in their glycosylation status in the Irish cohort [ Time Frame: 2 years ]
    Glycosylation analysis: IgG N-glycan analysis (serum test)

Information from the National Library of Medicine

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Ages Eligible for Study:   5 Years to 40 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Classical galactosaemia
  • Q188R Genotype
  • On lactose-free diet
  • No complications, condition well controlled
  • Male/femal adults and children aged between 5-12 yrs.
  • Informed consent /assent
  • Patient attend the Galactosaemia Clinic, NCIMD Dublin

Exclusion Criteria:

  • Complications, such as cataracts
  • Galactosaemia varaint, no Q188R-Genotype
  • Poor compliance
  • Intercurrent illness
  • Individual may not complete follow up
  • Children below 5 years of age
  • Unable to provide informed consent
  • Patient not under the care of Galactosaemia Clinic, NCIMD Dublin

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02218632

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National Centre for Inherited Metabolic Disorders, Children's University Hospital, Temple Street
Dublin, Ireland, 1
Sponsors and Collaborators
Children's University Hospital, Ireland
Health Research Board, Ireland
Medical Research Charities Group Ireland
University College Dublin
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Principal Investigator: Eileen Treacy, MD, Prof University Children's Hospital Dublin Irleland
Publications of Results:
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Responsible Party: Children's University Hospital, Ireland Identifier: NCT02218632    
Other Study ID Numbers: 12020
grant PAC number 12.64 ( Other Grant/Funding Number: MRCG/HRB )
First Posted: August 18, 2014    Key Record Dates
Last Update Posted: August 18, 2014
Last Verified: August 2014
Keywords provided by Children's University Hospital, Ireland:
Additional relevant MeSH terms:
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Brain Diseases, Metabolic, Inborn
Brain Diseases, Metabolic
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Carbohydrate Metabolism, Inborn Errors
Metabolic Diseases