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8/8/2019 3.6 Rubella Infection and Other Factors Associated With
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17 February 1979 SA MEDICAL JOURNAL 245
Rubella Infection and Other Factors Associated withCongenital
Cataracts in Cape Town
A. KIPPS,SUMMARY
D.SEVEL, JANET McINTYRERESULTS
An ana lysis of 56 pat ient s w ith congeni ta l cat arac ts
wasmade to detennine which factors played a role in the causation
of these lenticular defects in Cape Town. There isgood evidence
that 16% of the defects were caused byintra-uterine rubella virus
infection and that a further 30%were hereditary in origin.
S. Atr. med. I., 55, 245 (1979).Recent World Health Organization
statistics estimate thatthere are 40 million blind people in the
world, and that15 - 25 million blind people are suffering from
preventableor easily curable blindness.' Infectious agents are said
tobe the most common cause of blindness, but congenitalrubella
infection is not listed as one of them. Cataractis noted as a
'frequent cause of blindness in o lde r agegroups', but this
specifically excludes the 'relatively rarecongenital condi tions'
which cause cataracts!
In order to gain some measure of the f requency withwhich in tra
-ut erine rube lla infection migh t lead to cataract formation in
the local population, an analysis wasmade of 56 patients wi th
congenital cat aract s seen in theCape Town group o f teaching
hospitals during the 7-yearperiod 1971 - 1977.For the purpose of
this investigation congenital cataracts are def ined as those lens
opacities which interferewith normal vision, and which appear
during the firstyear of life; since they may not always be apparen
t a tbirth.
MATERIALS AND METHODSLens aspirates were taken from one or both
eyes of48 patients for rubella virus isolation.Blood samples did
not regularly accompany the lensmaterial; from 15 patients lens
material only was received.From 8 patients with congenital
cataracts blood alonewas received, because the lens aspiration had
not yet beenperformed. In a few instances blood was also
receivedfrom the pat ient 's mother.Rubella virus isolation and
haemagglutination inhibition(HAI) tests fo r rubella-specific IgO
and IgM Il-globulinswere performed by methods described in an
earlier article.'Virus Research Unit, Department of Bacteriology,
and De-partment of Ophthalmology, University of Cape TownA. KIPPS,
M.D. , F .R .C . PATH.D. SEVEL, M.B. CH.B., PH .D . , F .C .S.
(S.A. ), D.O. (Present address:LSU Eye Center, New Orleans,
Louisiana, USA).lA ET Md TYRE, M.B. B.S.Date received: 3 October
1978.
Of the 56 patients, 32 were male and 24 female. Therewere 40
Coloured patients, 10 Whi tes and 6 Blacks. Nineteen of the
patients were under the age of 12 months ,while the remaining 37
varied in age from 1 to 19years. There were 44 patients with
bilateral cataracts and12 with unilateral lens opacities.Congenital
rubella infection was suspected on clinicalgrounds in 9 of the 56
pat ients because of the presence
of one or more of t he following features in addition tothe
congenital cataract: congenital heart disease, deafness,mental
retardation or hepatosplenomegaly. In Table Ithe patients are
grouped according to the nature of thespecimens received in the
laboratory. In group I, only2 patients had clinical evidence of
rubella, and from thelenses of both of these patients rubella virus
was isolated.In group 11, 6 of th e 8 pat ients had clinical signs
suggestive of congenital rubella. These 6 infants had rubellaIgO
levels varying from 1 in 64 to 1 in 256, and in 3of them
rubella-specific IgM was demonstrated. Onepatient in group II I was
suspected on clinical groundsof having congenital rubella. The
rubella IgO level was1 in 64, but the test for IgM ant ibody was
not done.Three days after the birth of this child, however,
themother's serum had a rubella antibody level of 1 in 256,which
might suggest that rubella infection had occurredduring pregnancy.
These 9 patients were all under 9months of age.
The laboratory tests thus confirmed the diagnosis in 5of the 9
patients, and gave good support for the diagnosisof congenital
rubella in the remaining 4 patients. This suggests that in 16{, of
the patients with congenital cataractsrubella infection had played
a part as a causal factor.Congenital rubell a infection was not
seriously considered in the 22 patients who had no detectable
rubellaantibodies at the lowest serum dilution (l : 8) tested.
Therewere, however, 13 patients in group TII with rubella HAIant
ibodies varying in t it re from 1 in 16 to 1 in 256. Asthese
patients were aged 1 - 19 years, postnatal infectionscould not be
excluded to account for the antibodies! Nonehad clinical evidence
of congenital rubella.Familial cataracts figured prominently. There
were 13children with one parent and / or one or more
siblingssuffering from congenital cataracts. In one family, afather
and all 3 children had congenital cataracts, and inanother fami ly
tills was also the case with a mother andall 3 of her children. In
all 6 children the cataracts werebilateral. Two other types of
defect were encountered:3 pat ients had Down syndrome (due to a
well-definedchromosomal abnormality) and 1 patient presented with
amandibulofacial abnormality of the Pierre Robin syndrome (not so
ce rta in ly familial in origin). In these 17
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8/8/2019 3.6 Rubella Infection and Other Factors Associated With
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246 S A M ED IE SE T YD SK RIF 17 Februarie 1979TABLE I.
ANALVSIS OF INVESTIGATIONS FOR RUBELLA VIRUS INFECTION OF 56
PATIENTS WITH CONGENITALCATARACTS
Number of Rubella Confirmationpatients Clinical virus Rubella
Rubella of or goodwith evidence of isolated HAI anti- HAI anti-
support for
Specimens congenital congenital f rom lens bodies bodies not
congenitalGroup received cataract(s) rubella aspirate detected
detected rubella
I Lens aspirate 15 2 2 2/2.only11 Blood only 8 6 6 2 6/6III Lens
a s p i r a ~ e 33 1 0 13 20 111
and bloodTotal 56 9 2 19 22 9/9
HAI haemagglutination inhibition.
TABLE H. COMPARISON OF THE DISTRIBUTION OFCONGENITAL CATARACTS
IN ASSOCIATION WITH OTHERFACTORS IN DIFFERING GEOGRAPHICAL
REGIONS
Certain metabolic disorders are associated with the development
of congenital cataracts, bu t none was encountered in this series.
Likewise, cytomegalovirus and toxoplasma infections in pregnancy
may occasionally be associated with congenital cataracts.
Antibodies to these twoagents were titrated in the available 41
sera, bu t in nosingle instance could an association between the
agent an dthe cataract be established with any degree of
certainty.
The incidence of familial cataracts varies from 8% to23%;
excluding those associated with one of the numerous syndromes
caused by known genetic defects, of whichDown syndrome is one, and
the Pierre Robin syndromepossibly another. In Table II the relat
ive incidence ofrubella, an d hereditary and other presumed causes
of congenital ca taracts are shown by comparison of data fromtwo
reports with those of the present series. In patients withDown
syndrome, abnormalities of the eyes are frequent,with cataracts
tending to develop at the end of the firstdecade, bu t congenital
cataracts are much less common.In many patients with congenital
cataracts the familialorigin of the cataract cannot be ascertained
unt il subsequent siblings or generations are born. Such examples
areincluded with the sporadic cases, and contribute to thoselisted
as being of unknown cause.
patients, representing 30% of the total in this series,
thecataracts were most likely genetic in origin.
DISCUSSIONTh e importance of a study of congenital cataracts in
anygeographical region is that some of them at least may
bepreventable. Those caused by rubella can be forestalled
byimmunization of the susceptible mothers-to-be; some ofthose of
hereditary origin by genetic counselling; and somedu e to metabolic
defects, e.g. galactosaemia, by early treatment.'
Th e problem involves not only those persons renderedtotally
blind, bu t also those whose vision is so impairedas to limit
development, education and employment, andto enforce dependency on
the community or family.'Patients with congenital rubella
cataracts, for example, area severely handicapped group; those with
bilateral cataracts, according to one report: were so subnonnal
that 20ou t of 31 were confined to institutions. Those with
unilateral cataracts were much better able to adapt to
theirhandicaps.Rubella is a common cause of congenital
cataracts,which results from a direct invasion of the lens by
rubella virus in up to 20% of all cases: This incidence is higherin
developed countries where rubella infections may bedelayed, leaving
a greater proportion of pregnant womensusceptible to infection than
the 6 - 10% reported for CapeTown" In this report 16% of children
with congenital cataracts were presumed to have ha d intra-uterine
rubellainfection, a figure which might have been greater if the13
patients in group II I could have been more preciselyassessed.No t
to consider th e 22 patients with cataracts possiblycaused by
rubella, bu t without detectable rubella antibodies, may have been
unjustified. It has been shownthat, among 270 children known to
have congenital rubella, 50 (18,5'%) had no detectable HA I
antibodies by their5th birthday.T Others have reported children
with congenital rubella, bu t in whom antibodies to rubella
viruswere never detected. Nevertheless, there was no
clinicalevidence of congenital rubella, although the ages of
these22 patients varied from 4 months to 9 years.
Cape Town(56)
(present Australia"Association series) (136)
Rubella C%) 16, t 21,1Familial C%) 23,2 7,3Down syn-drome C%)
5,3 6,4Other syn-dromes C%) 1,8 5,5
Unknowncauses C%) 53,6 59,7
Nigeria'(26)7,719,2
3,869,2
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8/8/2019 3.6 Rubella Infection and Other Factors Associated With
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17 February 1979 SA MEDICAL JOURNAL 247I t is hoped that this
brief analysis will stimulate aninterest in the problem and
encourage practit ioners tomake use of genetic counselling and
rubella vaccination
to reduce the incidence of this serious physical handicapand its
inevitable consequences.REFERENCES
1. Wkly epidem. Rec., 53, 165 (1978).2. Leading article (1976):
Bri t. med. I. , 2. 788.
3. Merin, S. in Goldberg, M. F. . ed. ( 1974) : Gen
