To investigate if a vitamin B12 deficiency has a higher prevalence in LHON patients, during the acute phase of visual loss, then in a normal population.
ID
Source
Brief title
Condition
- Vision disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Prevalence of a vitamin B12 deficiency in the LHON and control population.
Secondary outcome
Cause of vitamin B12 deficiency in the LHON patients
Background summary
Leber Hereditary Optic Neuropathy (LHON) is an optic neuropathy, leading to
visual loss at a relative young age. In most patients a mutation in
mitochondrial DNA can be demonstrated. This mutation can lead eventually to a
apoptosis of retinal ganglion cells and their axons. These axons form the optic
nerve. Not all LHON carrirers develop an optic neuropathy. It is known that
the expression of LHON can be influenced by external factors. Smoking is mainly
accepted as a precipitating factor.
A vitamin B12 deficiency can also lead to an optic neuropathy. The clinical
signs of this optic neuropathy resembles that of LHON. Vitamin B12 is involved
in the regulation of biochemical processes of mitochondria (methionin
synthetase). In the literature, a vitamine B12 deficiency is not reported as a
risk factor for the development of an optic neuropathy in patients with a
positive LHON mutation. However, both the LHON mutation as the vitamine B12
deficiency have their origin in the mitochondrial metabolism. There are some
case reports suggesting a link between these two factors.
Recent recommendations report that a vitamin B12 deficiency can be overlooked
by a simple serum measurements of only vitamin B12. Measurement of
methylmalonic acid (MMA) and homocystein (HC) give a much higher sensitivity.
Both are metabolites in pathways regulated by vitamin B12 and become elevated
in a deficiency.
In this way, in a two years period, we recently diagnosed a vitamin B12
deficiency in two LHON patients. These were the only two new LHON diagnosed at
our department during that period. Also, a few years ago we have diagnosed
vitamin B12 deficiencies in three more LHON patients. These three patients were
published as case reports. These data do suggest that a vitamin B12 deficiency
can precipitate an optic neuropathy in LHON carriers.
Study objective
To investigate if a vitamin B12 deficiency has a higher prevalence in LHON
patients, during the acute phase of visual loss, then in a normal population.
Study design
Prospective case-control
Intervention:
-bloodmeasurement of vitamin B12, MMA, HC, folic acid, Hb, Ht, MCV in LHON
patients and controls
- if an vitamin B12 deficiency is detected, a referral to inernal medicine will
follow for evaluation of the cause of deficiency
Study burden and risks
The burden of the participants is a single blood examination (venapunction)
Postbus 30.001
9700 RB Groningen
NL
Postbus 30.001
9700 RB Groningen
NL
Listed location countries
Age
Inclusion criteria
LHON patients:
-clinical characteristics of LHON
-proven LHON mutation
- recent loss of vision (not longer then half a year);Control patients:
- same gender as LHON patient for which will be matched
- same age (+/- 3 years) as LHON patient for which will be matched (but not younger then 18 years)
Exclusion criteria
LHON patient
- younger then 18 years;Control patients
-known optic neuropathy
-actual treatment by medical specialist (except ophthalmologist)
- known bowel disease, for which patient receives treatment
- actual neurological disease, for which patient is under treatment
- known renal dysfunction
- known diabetes mellitus
- known thyroid disease
- known anemia
- veganistic diet
- excess alcohol intake (> 4 units a day)
-pregnancy
- medication: gastric acid secretion inhibitors, colchicine
- smoking
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL36739.042.11 |