HUT (Hutterite)

Inheritance: autosomal recessive
Genes: unknown

congenital cataract

Nystagmus
Amblyopia
Poor vision
Blindness

Cataract, Juvenile

Clinical Characteristics

General description (for patients):

Cataracts, or opacification of the lens, come in many varieties with a highly variable age of onset and progression.  Most are age-related and occur in adults, usually after the age of 50. Those with their onset during childhood are usually part of a systemic disease but rare cases occur in infancy, early childhood, or adolescence with no other health problems.   Some such early onset lens opacities are familial and appear to be genetic in origin.  Many cataracts are mild, and, if vision is not impacted, they may go undetected without an eye examination.  Other patients are less fortunate and can suffer severe vision loss.  Fortunately, modern cataract surgery is highly successful at all ages and those with significant visual impairment can have complete restoration of sight.  Cataracts in children under the age of8 years, however, can lead to permanent vision loss secondary to amblyopia, or 'lazy eye', if they are not removed prior to that time.

Medical description:  

Congenital cataracts come in a wide variety and have a variable age of onset.  Those developing in utero or within the first two years of life are considered congenital but others occurring later in children are considered juvenile cataracts.  Many in children are part of systemic disorders (such as galactosemia) while others are part of ocular syndromes (Leber’s congenital amaurosis).  Isolated congenital cataracts can be inherited in autosomal dominant or autosomal recessive patterns.  Most importantly, cataract surgery, even in infancy is highly successful in restoring vision.  To prevent amblyopia in children, however, a clear ocular media must be restored by the age of 8 years, or as soon as the lens opacities are significant.

Genetics:

Numerous genes are involved with most causing syndromal disease.  Few specific mutations have been identified among familial isolated cataracts.  Several related Hutterite pedigrees with multiple affected individuals have been reported, however. The diagnosis was made in nine individuals at about two to five years of age but there was anecdotal information suggesting several may have had cataracts from infancy.  If so, they must have been minimal since post-operative vision was generally returned to 20/25-20/20 and none had permanent nystagmus.  However, no fundus examination was reported and it is not certain if the cataracts were part of an ocular syndrome.  No systemic disease was present.  No mutation or linked chromosomal locus has been reported but parental consanguinity and the segregation ratio among the sibships suggest autosomal recessive inheritance.

Treatment:

Cataract surgery.

Prognosis:

Excellent if the opacification is removed before the onset of amblyopia.

Ancillary treatments and support:

Vision training and low vision aids for those with significant amblyopia. Support and treatment for associated systemic disorders as indicated.

Specialists and specialty centers:

Pediatrician, ophthalmologist.

References:

Shokeir, M.H.K., and Lowry, R.B.:  Juvenile Cataract in Hutterites.  Amer. J. Med. Genet. 22: 495-500, 1985.  PubMed ID: 4061486