Re: Re: Question re: MELAS diagnosis

[Guest guest]

I just thought it worth mentioning that I have just been diagnosed with MELAS

A3243G via urine cells. My mito doc in Sydney believes that this is a more

reliable source than blood test. pamela

Re: Re: Question re: MELAS diagnosis

a

I'm not sure about where to have it tested, but would think that one

of the mito labs would be the best place - Dr. Hoppel, Dr. Shoffner,

Dr. Damouro.

If you have a mtDNA defect and he has the same mother, than he would

have to carry the defective gene. Maybe a mito doc would diagnosis him

based on this.

laurie

> Dear Mitoldies.

>

> I have a question regarding a diagnosis. I am confirmed with MELAS as are

> my children. My mother, now deceased, is presumed to have had MELAS,

likewise

> her mother, based on their medical histories. My brother was recently

> tested for MELAS and the results were negative. This does not make sense.

I can

> only imagine a clerical error, a lab error, an error in handling the lab

> sample, which was blood, or a lack of test sensitivity. He has a life-long

> learning disability, cardiomyopathy, muscle weakness, prediabetic, no

hearing loss

> yet, but has sleep apnea for which he uses a CPAP.

>

> My brother is currently applying for SSI based on his clinical signs. The

> MELAS diagnosis would provide the evidence to make his temporary supplement

> permanent. Besides retesting, do you have any suggestions? If retesting,

then

> with whom and where? The rest of us have the A3243G mtDNA mutation albeit

at

> less than 10% heteroplasy. This mutation can be determined with only a

> blood test if honing in on this specific defect.

>

> Thank you for your help.

>

> a

>

>

>

>

[Guest guest]

Is muscle from a frozen biosy considered reliable for MELAS testing?

Any thoughts would be appreciated.

Hugs,

Marie

_____

From: [mailto: ] On Behalf

Of pamelama33

Sent: Wednesday, October 19, 2005 5:52 AM

To:

Subject: Re: Re: Question re: MELAS diagnosis

I just thought it worth mentioning that I have just been diagnosed with

MELAS A3243G via urine cells. My mito doc in Sydney believes that this is a

more reliable source than blood test. pamela

Re: Re: Question re: MELAS diagnosis

a

I'm not sure about where to have it tested, but would think that one

of the mito labs would be the best place - Dr. Hoppel, Dr. Shoffner,

Dr. Damouro.

If you have a mtDNA defect and he has the same mother, than he would

have to carry the defective gene. Maybe a mito doc would diagnosis him

based on this.

laurie

> Dear Mitoldies.

>

> I have a question regarding a diagnosis. I am confirmed with MELAS as

are

> my children. My mother, now deceased, is presumed to have had MELAS,

likewise

> her mother, based on their medical histories. My brother was recently

> tested for MELAS and the results were negative. This does not make

sense. I can

> only imagine a clerical error, a lab error, an error in handling the

lab

> sample, which was blood, or a lack of test sensitivity. He has a

life-long

> learning disability, cardiomyopathy, muscle weakness, prediabetic, no

hearing loss

> yet, but has sleep apnea for which he uses a CPAP.

>

> My brother is currently applying for SSI based on his clinical signs.

The

> MELAS diagnosis would provide the evidence to make his temporary

supplement

> permanent. Besides retesting, do you have any suggestions? If

retesting, then

> with whom and where? The rest of us have the A3243G mtDNA mutation

albeit at

> less than 10% heteroplasy. This mutation can be determined with only a

> blood test if honing in on this specific defect.

>

> Thank you for your help.

>

> a

>

>

>

>

[Guest guest]

Pamela, Did your doctor give any reason for why he believes urine cells are

more reliable than blood? I was under the impression that any good source of

DNA, whether the defect is in nDNA or mtDNA, would produce the same results

since specific mutations such as A3243G can only be confirmed through

genetic screening. This is a new twist to me, so I'm curious about his

reasoning.

Thanks.

Barbara

> I just thought it worth mentioning that I have just been diagnosed with

MELAS

> A3243G via urine cells. My mito doc in Sydney believes that this is a

more reliable

> source than blood test. pamela

[Guest guest]

Hi Marie,

Respiratory chain enzyme activities in skeletal muscle: 1) If a muscle biopsy is

performed to pursue a diagnostic workup, then test respiratory chain enzyme

activities. 2) Patients with MELAS have been found to have marked deficiency in

the activity of complex I of the respiratory chain. 3) Some patients with the

disorder have a combined deficiency of complex I and complex IV.

Mitochondrial DNA mutation analysis on blood, skeletal muscle, or hair

follicles: 1) Individuals with more severe clinical manifestations of MELAS

generally have greater than 80% mutant mtDNA in stable tissues such as muscle.

2) In rapidly dividing cells, such as the components of the hematopoietic

lineages, A3243G mutation may segregate to extremely low levels, making genetic

diagnosis from blood difficult. 3) Confirming the presence or absence of

mutation MAY require a muscle biopsy with analysis of skeletal muscle.

Marie mitomom@...> wrote:

Is muscle from a frozen biosy considered reliable for MELAS testing?

[Guest guest]

Marie, A biopsy, frozen or fresh, could confirm the presence of deficiencies

in one of the respiratory chain complexes, but that would not specifically

confirm MELAS. History can be very suggestive and some patients with

confirmed OXPHOS deficiencies are given a diagnosis of likely MELAS on that

basis. Certainty comes only from genetic screening for known MELAS

mutations.

Genetic screening does not require a muscle biopsy, but can be done with any

tissue that yields good mtDNA. Most labs have their protocols and

preferences set for tissue. My nDNA and mtDNA screening was done with

lymphoblasts extracted from blood shipped on dry ice, and also with dried

blood and buccal cells extracted from a cheek swab. In 1999 I was screened

for 11 known mtDNA mutations, including 2 known MELAS mutations, by Lee-Jun

Wong at town U lab, DC.

> Is muscle from a frozen biosy considered reliable for MELAS testing?

>

> Any thoughts would be appreciated.

>

> Hugs,

>

> Marie