Neurology India, Vol. 50, No. 3, Sept, 2002, pp. 371-372
Sjogren - Larsson Syndrome : A Case Report
A.K. Dhanuka, M. Gupta
Correspondence to : Dr. A.K. Dhanuka, Dayanand Medical College, 907 / 2A, Tagore Nagar, Ludhiana- 141001, Punjab, India.
Code Number: ni02105
Two male siblings aged 8 and 11 years, born of non-consanguineous parents, presented with classical triad of congenital ichthyosis, mental retardation and spastic diplegia. They had no eye, hair, nails and teeth changes. MRI showed diffuse dysmyelination.
Key words : Congenital ichthyosis, Mental retardation, Spastic diplegia, Sjogren larsson syndrome.
Sjogren - Larsson Syndrome (SLS) is an autosomal recessive condition with a triad of ichthyosis, mental deficiency and spastic diplegia or tetraplegia. In addition, a characteristic retinopathy has been noted.1 SLS is caused by mutation in the gene for fatty aldelyde dehydrogenase (FALDH).2 This enzyme catalyzes the oxidation of long chain aldehyde to fatty acids.3 Due to deficiency of this enzyme, there is accumulation of aldehyde-modified lipids or fatty alcohol which probably disrupts the barrier function of the skin and white matter of the brain. It occurs in all races and over 200 cases worldwide have been reported.4 Two cases in an Indian family are reported.
Two brothers, aged 8 and 11 years, presented with generalized dryness of skin since birth and difficulty in walking for 2-3 years. There was no history of consanguinity in parents and none of the family members on the maternal or paternal side were affected. The boys were delivered at full term by a normal vaginal delivery, with no history of prolonged labor. The children were short in stature and had history of delayed milestones and speech development. They were not performing well at school.
Cutaneous examination revealed generalized dryness of skin with fine scales over the trunk and large, somewhat adherent, scales on the extremities. The flexures were involved and showed lichenification. The palms and soles were rough to feel. The hair and nails were normal and the teeth showed no abnormalities. The testes were normal. There was no organonmegaly. Neurological examination revealed moderate mental retardation in both of them. IQ of elder child was 55 while that of younger one was 65. The elder child had dysarthria as well. Both the boys had a spastic gait with brisk deep tendon reflexes in all the four limbs and extensor plantar responses. Power in lower limbs of both the children was grade 4/5 on MRC scale. Upper limbs had normal power. These features were more marked in the elder sibling, as were the cutaneous findings. There were no sensory, extrapyramidal or cerebellar signs in either of the cases. A detailed eye examination revealed no abnormality. The lipid profile was normal. Skin biopsy showed marked hyperkeratosis, acanthosis and presence of granular layer. MRI revealed bilateral diffuse white matter hyperintensities on T2WI suggesting dysmyelination. Corpus callosum were involved (Fig. 1). No atrophy or circumscribed lesions were seen on MRI. Nerve conduction studies were normal. The histochemical and biochemical assays like histochemical analysis of hexanol dehydrogenase in skin and biochemical assay of leukocytes or fibroblasts for fatty aldehyde dehydrogenase (FALDH) were not available.
The diagnosis of SLS is invariably delayed, similar to other rare multisystem diseases. The cutaneous symptoms of scaling hyperkeratosis is usually present at birth, while other symptoms are lacking. Minor neurologic signs are usually missed. Later, when neurologic signs appear, the neurologists may fail to recognize the co-existence of cutaneous disease especially if it is mild or being treated with moisturizing lotions.5 Diagnosis of SLS is suggested when both neurologic and cutaneous symptoms are recognized simultaneously.
One third of the patients exhibit a distinctive and perhaps pathognomic presence of glistening white dots surrounding the macular region of retina, which first appears after several years of age.6 This finding was not present in our cases, however it does not exclude the diagnosis of SLS as it is present in only one third of cases and may appear later in life. Brain MRI showed evidence of white matter disease characterized by dysmyelination or delayed myelination. Proton magnetic resonance spectroscopy (MRS) of the brain revealed unidentified lipid peaks in the white matter.6 The differential diagnosis is from other neuroichthyotic disorders and FALDH activity in skin fibroblasts and leukocytes would confirm the diagnosis.7 However, this test is not available in India. The clinical triad of congenital ichthyosis in the characteristic distribution, spastic diplegia and mental retardation eliminate the possibilities of congenital ichthyosiform erythrodermas with neurologic signs, neutral lipid storage disease and other ichthyosiform syndromes. A simple clinical examination of the skin may solve the problem and clinch the diagnosis which otherwise seems most difficult.
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