Definition of Ichthyosis, spasticity, oligophrenia syndrome
Ichthyosis, spasticity, oligophrenia syndrome definition - medical term Also known as the Sjogren-Larsson
syndrome, this is a genetic (inherited) disease characterized by a triad of clinical
findings consisting of ichthyosis (thickened fish-like skin), spastic paraplegia
(spasticity of the legs) and mental retardation (oligophrenia is an old word for
mental retardation).
T he skin changes in the Sjogren-Larsson syndrome are similar to those in congenital
ichthyosiform erythroderma, a genetic disease that results in fish-like, reddened
skin. Hyperkeratosis (thickening of the skin) is a regular feature. Ecchymoses (bruises)
are present at birth or soon after in the Sjogren-Larsson syndrome. Sweating is
normal.
The spasticity can also affect the arms as well as the legs, resulting in spastic
paraplegia. The mental retardation is significant. Most of the patients never walk.
About half the patients have seizures.
Eye problems are also part of the syndrome. About half of cases have pigmentary
degeneration of the retina. Glistening white dots on the retina are characteristic.
People with Sjogren-Larsson syndrome tend to be unusually short.
Sjogren in 1956 (and Sjogren and Larsson in 1957) suggested that all Swedes with
the syndrome are descended from one ancestor in whom a mutation (a genetic change)
occurred about 600 years ago. This mutation is now present in at least 1% of the
population in northern Sweden. This phenomenon is called founder effect (because
everyone is descended from one "founder" within what was once a tiny group of people).
The gene for the Sjogren-Larsson syndrome has been found situated on chromosome
number 17 (in band 17p11.2). The presence in a person of one copy of the gene (the
heterozygous state) is harmless. However, if two gene carriers (heterozygotes) mate,
the risk for each of their children is one-quarter to receive both of their Sjorgren-Larsson
genes and to have the syndrome. The inheritance of Sjogren-Larsson syndrome is thus
termed autosomal (non-sexlinked) recessive.
The laboratory findings are critically important. There is a deficiency of an
enzyme called fatty aldehyde dehydrogenase 10 (FALDH10)in the Sjogren-Larsson syndrome.
The syndrome is due to a deficit of FALDH10 and the gene for the Sjogren-Larsson
syndrome gene is synonymous with the FALDH10 gene.
Some clinical improvement has been reported to occur with fat restriction in
the diet and supplementation with medium-chain triglycerides.
Persons of diverse and different ethnic origins are now known with the Sjogren-Larsson
syndrome. They include not only Swedes but, for example, members of families of
other European, Arabic, and native American (AmerIndian) descent. This is evidence
for genetic homogeneity (what appears clinically to be one genetic disease is in
reality due to a diversity of mutations. All of the mutations causing Sjogren-Larsson
syndrome have proved to be changes in the FALDH gene.
The Sjogren-Larsson syndrome is sometimes called the T. Sjogren syndrome to distinguish
it from the sicca syndrome, which was described by Henrick Sjogren, a Swedish ophthalmologist.
The Sjogren of the Sjorgren-Larsson syndrome was Torsten Sjogren (1896-1974), professor
of psychiatry at the celebrated Karolinska Hospital in Stockholm and a pioneer in
modern psychiatry and medical genetics. Tage Larsson was similarly a Swedish physician.
The Sjogren-Larsson syndrome is also known as SLS; fatty alcohol: NAD+ oxidoreductase
deficiency (FAO deficiency); fatty aldehyde dehydrogenase deficiency (FALDH deficiency);
and fatty aldehyde dehydrogenase 10 deficiency (FALDH10 deficiency).
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