Microcephaly, Congenital Cataracts, and Psoriasiform Dermatitis
Patient Information
Characteristics
Background and History
This is a recently described condition based on reports of only a few patients. It involves multiple systems including skeletal, neurological, and lipid (fat) metabolism.
Clinical Correlations
The small head (microcephaly) and short stature are evident at birth. A dry, red, and scaly skin may be present from birth while some individuals develop a generalized skin condition that superficially resembles psoriasis which may wax and wane throughout life. Physical and mental development are slow and most patients never achieve normal growth. Joints may be involved with pain and stiffness and some individuals develop contractures. Some cognitive deficits are nearly always present.
Infants have bilateral cataracts but vision levels even in adults have not been reported. Some patients have a smoldering inflammation of the eyelids.
The cholesterol synthesis pathway is abnormal and the blood contains decreased amounts of cholesterol while immunoglobulins such as IgA and IgE are increased.
Genetics
Inheritance
This condition is expressed when both members of a pair of genes are changed (mutated) and therefore it is transmitted in an autosomal recessive pattern. Both parents of an affected individual carry a single changed gene and are clinically normal although some have mildly elevated levels of certain members of the cholesterol precursors. When both parents carry the mutation their children each have a 25% risk of developing this condition.
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.
Diagnosis and Prognosis
Since only a few families with this condition have been reported, little is known regarding the natural history. However, it is a chronic condition with lifelong health issues, both physical and mental. The diagnosis might be made in infants based on the small heads and skin changes. Pediatricians, orthopedists, ophthalmologists, and dermatologists would likely collaborate on the diagnosis.
Treatment with cholesterol supplements has been reported to improve symptoms. Topical antibiotic drops or ointment could help control the eyelid infections. Physical therapy is recommended for joint mobility and the prevention of contractures. Conventional treatments for psoriasis may be helpful.
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