A Guide for Parents, Friends, and Professionals (©2000)
I. Frequently Asked Questions
What is Lowe syndrome?
Lowe syndrome (LS) is a rare genetic condition affecting males that
causes physical and mental handicaps and medical problems. Also called
the oculo-cerebro-renal syndrome of Lowe (OCRL), it was first described
in 1952 by Dr. Charles Lowe and colleagues.
What causes Lowe syndrome?
Lowe syndrome is caused by a defective gene that results in the deficiency
of an enzyme called phosphatidylinositol 4,5-biphosphate 5 phosphatase.
This enzyme is essential to normal metabolic processes that take place
in a small part of the cell called the Golgi apparatus. Because of the
enzyme deficiency, cell functions that are regulated by the Golgi are
abnormal, leading to various developmental defects including cataracts
and problems in the brain and kidneys. How the enzyme deficiency leads
to these defects is not yet completely understood.
Why can't the missing enzyme just be replaced?
Scientists must first better understand the subtle imbalance caused
by the biochemical defect. It is possible that overcorrection could
be just as harmful as the original lack of the enzyme. In addition,
there is currently no method available to target therapies to the Golgi
apparatus, the small subcompartment of the cell where the LS enzyme
is located.
How is LS inherited?
The LS gene is located on the X-chromosome. Only males can actually
have the condition. Females who have the LS gene are carriers. In some
cases, LS is the result of an original mutation and the mother is not
a carrier.
Can LS be prevented?
In families in which a case of LS has occurred, a slit-lamp eye examination
can help determine carrier status of at-risk females. Research currently
underway may lead to a more definitive genetic test for carrier status.
Various family planning options are available, including prenatal testing.
Families should consult with a geneticist to learn more about their
options.
Where are diagnostic tests done?
To diagnose LS, a small skin sample is taken and sent to the Biochemical
Genetics Laboratory at Baylor College of Medicine in Houston, Texas.
Prenatal diagnosis is also provided at this lab. Physicians may make
arrangements for these tests by calling 1-800-246-2436 or 713-798-4982
or through e-mail at: bioc@bcm.tmc.edu.
What are the common features of LS?
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Cataracts in both eyes, found at birth or shortly after
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Glaucoma (in about half the cases)
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Poor muscle tone and delayed motor development
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Mental retardation, ranging from borderline to severe (in a few cases intelligence may be normal)
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Seizures (in about half the cases)
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Significant behavior problems (in many, but not all, cases)
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Kidney involvement ("leaky" kidneys, or renal tubular acidosis)
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Short stature
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Tendency to develop rickets, bone fractures, scoliosis, and joint problems
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Maximum life span of about 35-40 years due to progressive kidney failure, although deaths have occurred at earlier ages due both to renal failure and to other causes. Life expectancy may increase as knowledge increases and new treatments are developed.
How is LS treated?
There is no cure, but many of the symptoms can be treated effectively
through medication, surgery, physical and occupational therapies, and
special education.
What about research?
In 1992 the gene that causes LS was found. In 1995 researchers discovered
that the gene defect causes an enzyme deficiency. Researchers continue
to investigate the function of the gene and the complicated biochemistry
and cellular mechanisms of LS. Other areas of research in recent years
include behavior problems and clinical care.
What are boys with LS like?
Generally, they are affectionate and sociable, love music, and have
a great sense of humor.
