The Sjögren-Larsson syndrome

Ichthyosis in Sjögren-Larsson syndrome reflects defective barrier function due to abnormal lamellar body structure and secretion

Sjögren-Larsson syndrome is a genetic disease characterized by ichthyosis, mental retardation, spasticity and mutations in the ALDH3A2 gene coding for fatty aldehyde dehydrogenase, an enzyme necessary for oxidation of fatty aldehydes and fatty alcohols. We investigated the cutaneous abnormalities in 9 patients with Sjögren-Larsson syndrome to better understand how the enzymatic deficiency results in epidermal dysfunction. Histochemical staining for aldehyde oxidizing activity was profoundly reduced in the epidermis. Colloidal lanthanum perfusion studies showed abnormal movement of tracer into the extracellular spaces of the stratum corneum consistent with a leaky water barrier. The barrier defect could be attributed to the presence of abnormal lamellar bodies, many with disrupted limiting membranes or lacking lamellar contents. Entombed lamellar bodies were present in the cytoplasm of corneocytes suggesting blockade of lamellar body secretion. At the stratum granulosum-stratum corneum interface, non-lamellar material displaced or replaced secreted lamellar membranes, and in the stratum corneum, the number of lamellar bilayers declined and lamellar membrane organization was disrupted by foci of lamellar/non-lamellar phase separation. These studies demonstrate the presence of a permeability barrier abnormality in Sjögren-Larsson syndrome, which localizes to the stratum corneum interstices and can be attributed to abnormalities in lamellar body formation and secretion.

Crystalline Retinopathies

Many types of crystalline retinopathies have been described, associated with a myriad of medical conditions ranging from chronic retinal conditions to inherited systemic diseases. This comprehensive review summarizes the different types of crystalline retinopathies, including their clinical presentations, diagnostic criteria, pathology, and treatment options.

Molecular genetics of the ichthyoses

The ichthyoses are a large, clinically, genetically, and etiologically heterogeneous group of disorders of cornification due to abnormal differentiation and desquamation of the epidermis. Although they differ in clinical features, inheritance, and structural and biochemical abnormalities of the epidermis, they often pose a diagnostic challenge. For each of the 12 ichthyoses and related disorders described here, the major disease genes have been identified and genotype-phenotype correlation have begun to emerge. The molecular findings reveal the functional importance and interactions of many different epidermal proteins and metabolic pathways, including major structural proteins (keratins, loricrin), enzymes involved in lipid metabolism (transglutaminase 1, lipoxygenases, fatty aldehyde dehydrogenase, steroid sulfatase, glucocerebrosidase, Delta8-Delta7 sterol isomerase, 3beta-hydroxysteroid dehydrogenase), and protein catabolism (LEKTI), peroxisomal transport and processing (Peroxin 7 receptor, Phytanoyl-CoA hydroxylase) and DNA repair (proteins of the transcription repair complex). This review highlights the spectacular advances in the molecular genetics and biology of heritable ichthyoses over the past decade. It illustrates the power of molecular diagnostics for refining disease classification, providing prenatal diagnosis, improving genetic counseling, and clinical management.

Redefining the Sjögren-Larsson syndrome: atypical findings in three siblings and implications regarding diagnosis

BACKGROUND

The Sjögren-Larsson syndrome is a rare condition characterized by ichthyosis, spasticity, and mental retardation. Patients have deficient activity of the aldehyde portion of the fatty alcohol:nicotinamide adenine denucleotide (NAD+) oxidoreductase complex.

OBJECTIVE

Our purpose was to describe atypical findings in three siblings with the Sjögren-Larsson syndrome and implications regarding diagnosis.

METHODS

Medical histories were taken and physical examinations performed on four siblings and their parents. Analysis of fibroblast fatty alcohol:NAD+ oxidoreductase or fatty aldehyde dehydrogenase activity (or of both) was determined in each.

RESULTS

Decreased fibroblast fatty alcohol:NAD+ oxidoreductase or fatty aldehyde dehydrognase levels (or both) were present in three of four siblings. The fourth sibling and the parents had levels similar to obligate heterozygotes. None of the affected siblings fulfilled the classic criteria for the syndrome.

CONCLUSION

Although all affected siblings had abnormally low activity of the fatty alcohol:NAD+ dehydrogenase complex, their clinical findings were variable. This divergence of clinical features in siblings has not been previously reported. We propose that deficient activity of the fatty alcohol:NAD+ dehydrogenase complex be considered part of the definition of the Sjögren-Larsson syndrome that would also include the probable, but not absolute, presence of ichthyosis, mental retardation, and spasticity.

Inherited ichthyoses: a review of the histology of the skin

The histology of skin biopsies from 46 cases of different forms of congenital ichthyosis was reviewed. Sections were examined for hyperkeratosis, follicular keratosis, appearance of the granular layer, epidermal thickness, tonofilament clumps, epidermal vacuolation, spongiosis, bullae and dyskeratosis, appearance of the basal layer, inflammation, mitoses, and adnexae. A detailed description of the histological features of each type of ichtnyosis studied is presented. Some ichthyoses can be recognized on routine hematoxylin and eosin staining (bullous ichthyosiform erythroderma, Netherton's syndrome, and neutral lipid storage disease); some forms require frozen sections to demonstrate fat (neutral lipid storage disease) or enzyme activity (Sjögren-Larsson syndrome). Protein electrophoresis and enzymology are necessary for X-linked recessive ichthyosis. A close liaison with the clinicians is essential for the diagnosis of all types of ichthyosis, and combined studies including routine histopathology, electron microscopy, and frozen sections may be required for the diagnosis.

The quantification of free sphingosine in the stratum corneum of patients with hereditary ichthyosis

Sphingosine is a long-chain base which provides the back-bone of all sphingolipid molecules. Free sphingosine is found in normal epidermis, especially in the stratum corneum. As a free molecule it may modify epidermal cell proliferation and differentiation through its inhibition of protein kinase C. Using a thin-layer chromatography technique we have demonstrated in vitro that the erythrodermic ichthyoses show significantly lower levels of stratum corneum sphingosine than the non-erythrodermic types. The exact in vivo significance of this finding is unclear, but free sphingosine may have an important role in determining the inflammatory component of the hereditary ichthyoses.

What syndrome is this? Sjögren-Larsson syndrome

Sjögren-Larsson syndrome is an inborn error of metabolism with its primary clinical manifestations being congenital ichthyosis, spastic hemiplegia or quadriplegia, and moderate to severe mental retardation. Definitive diagnosis can be made by measuring fatty aldehyde dehydrogenase activity in cultured skin fibroblasts. Treatment of dermatologic manifestations is best accomplished with topical emollients and frequent bathing or showering. Some evidence supports medium-chain triglyceride diets and oral retinoids. These modalities, however, remain controversial.

Sjögren-Larsson syndrome associated with the Dandy-Walker malformation: report of a case

The Sjögren-Larsson syndrome is defined as the association of ichthyosis, spastic diplegia or tetraplegia, and mental retardation. Although most cases described have come from the Swedish county of Vasterbotten, isolated reports from the United States and elsewhere do exist. Numerous neurologic abnormalities have been reported with this syndrome, including speech defects, seizures, and pyramidal tract disorders. Abnormal ophthalmologic findings are not rare. Previous studies with computerized tomographic (CT) scans have revealed no abnormalities of cranial anatomy. We report a 6-year-old boy with Sjögren-Larsson syndrome who had a Dandy-Walker malformation as demonstrated by diagnostic imaging by CT and magnetic resonance imaging scans. This case illustrates that developmental defects of the central nervous system can also occur in association with Sjögren-Larsson syndrome.

Ichthyosis. Reliability of clinical signs in the differentiation between autosomal dominant and sex-linked forms

The reliability of clinical signs to differentiate between autosomal dominant ichthyosis (ADI) or sex-linked ichthyosis (SLI) were assessed. SLI was defined as ichthyosis in combination with steroid sulphatase deficiency. Age of onset and format of the scales were found to be reliable signs to ascertain the diagnosis of ADI or SLI. The ADI-like appearance in histopathology seems to be of little diagnostic value.