OMIM ID:
Marinesco-Sjogren Syndrome
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Congenital cataracts are one of the cardinal features of Marinesco-Sjogren syndrome but lens opacities may have a later onset and may be progressive as well. Strabismus and nystagmus are sometimes present.
Systemic Features
Non-ocular features include cerebellar atrophy, psychomotor developmental delays, mental retardation, and muscle weakness. Dysarthria is common. The myopathy has its onset in childhood and is progressive with weakness, hypotonia, and atrophy eventually leading to total disability in some cases. Progression of motor dysfunction may, however, stabilize in some patients but at an unpredictable level. Infants are often ‘floppy babies’. MRI studies reveal cerebellar atrophy. Serum creatine kinase levels are increased and muscle biopsies show chronic myopathic changes. Skeletal features include short stature, pectus carinatum, and secondary kyphoscoliosis and foot deformities. Bone abnormalities may be seen in the digits.
Genetics
Inheritance
This is an autosomal recessive condition resulting from mutations in the SIL1 gene (5q31). It is sometimes confused with the condition known as congenital cataracts, facial dysmorphism, and neuropathy (604168) with which it shares some clinical features. The two conditions are genetically distinct since they are caused by mutations in different genes.
See also Muscular Dystrophy, Congenital Cataracts, with Cataracts and Intellectual Disability for a similar disorder caused by a different mutation.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.