A Guide for Parents, Friends, and Professionals (©2000)
III. Medical Features
Please note that advances in diagnostic testing for Lowe Syndrome have improved since this booklet was published. More information can be found at http://www.lowesyndrome.org/Lowe%20Syndrome/Diagnosis/overview.html.
A. Diagnosis
A definitive diagnosis of Lowe syndrome can only be made by testing
for the presence or absence of a specific enzyme in skin cells. In this
procedure, a small skin sample is taken from the patient, usually by
a local physician. The sample must be sent to a specialized biochemical
laboratory for culture and analysis. The Biochemical Genetics Laboratory
in the Department of Molecular and Human Genetics at Baylor College
of Medicine in Houston, Texas is the first (and currently the only)
laboratory that offers the test as a clinical service. Results of the
analysis are usually available in 4-8 weeks (because of the time required
to grow the skin cells in culture). Physicians may arrange for the test
by calling 1-800-246-2436 or 713-798-4982 or by e-mail at: bioc@bcm.tmc.edu.
A physician considers a diagnosis of Lowe syndrome when there are cataracts at birth, kidney dysfunction, and nervous system manifestations (such as hypotonia) in a male infant, especially if there is a family history indicating X-linked inheritance. The diagnosis of Lowe syndrome is usually made by a geneticist (a physician trained in genetics), but many other types of physicians have also made the diagnosis.
Before the development of the skin enzyme test in 1996 (see V. Research), diagnosing Lowe syndrome early in infancy was not always simple and straightforward. Although the cataracts and low muscle tone (hypotonia) are detectable at birth or shortly thereafter, other eye and nervous system manifestations may only develop later. Laboratory tests needed to detect kidney involvement may also not be abnormal immediately after birth (see Kidneys). Furthermore, the degree to which the kidneys, nervous system, and other organs are affected differs from person to person, even in the same family, and may change with age.
A deficiency of the Lowe syndrome enzyme in skin is the only finding
that is definitively diagnostic for Lowe syndrome. Affected children
are now typically diagnosed within the first few months of life due
to increasing knowledge about Lowe syndrome and availability of the
new enzyme test.
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