Indian Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 1984  |  Volume : 32  |  Issue : 2  |  Page : 81--84

Influence of birth rank and parental age on congenital and colobomatous defects


LC Dutta, H Bhattacharjee 
 Department of Ophthalmology, Medical College, Gauhati, India

Correspondence Address:
L C Dutta
Department of Ophthalmology, Medical College, Gauhati
India




How to cite this article:
Dutta L C, Bhattacharjee H. Influence of birth rank and parental age on congenital and colobomatous defects.Indian J Ophthalmol 1984;32:81-84


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Dutta L C, Bhattacharjee H. Influence of birth rank and parental age on congenital and colobomatous defects. Indian J Ophthalmol [serial online] 1984 [cited 2024 Mar 29 ];32:81-84
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Full Text

Congenital abnormalities in most of the cases are of obscure aetiology; heredity and certain biological factors are known to have influence on its occurrence. Effect of birth order is described in relation to certain sys�temic disease like Mongolism[1], Congenital pyloric stenosis, Apert's syndrome[2], con�genital heart disease and several other malformations. Parental age may also have some influence on congenital abnormalities. Literature on congenital ocular abnor�malities in respect of those factors is scanty. Murty[3] found 50% cases of congenital cataract in first birth order, whereas incidence of microphthalmos and congenital corneal opacity is less in first birth order than in second or third. Few authors[4],[5],[6] described the influence of parental age on the occurrence of congenital hereditary ocular diseases. This study is an attempt to find out whether there is any statistically significant co-relation bet�ween incidence of certain specific blinding congenital ocular abnormalities and biologi�cal factors like' parental age and birth rank of the affected individuals.

 MATERIALS AND METHODS



We have investigated 127 families of patients with various colobomatous defects of the globe and 45 families of patients with con�genital cataract independent of religion, sex and age (20 hours to 20 years). All the patients (if adults) and/or their attendants were thoroughly interviewed to elicit the family history of similar or any other congenital dis�eases; all the available members of the family of the affected persons upto three generations were also clinically examined (both ocular and systemic).

To find out the parental age at the time of birth both the parents are interrogated in a retrospective way and in those parents who failed to mention the exact age, their age is estimated by correlation with remarkable past events and other medical way of age determination.

While recording birth rank all the parental conceptions were taken into account. The data obtained thereof in relation to parental age and birth rank were statistically verified by Chi-square test.

 OBSERVATIONS



1. [Table 1] shows the various congenital ocular abnormalities. which were studied.

2. Incidence of congenital cataract is highest in second birth rank (14 out of 51 i.e. 27.45%). It is equally prevalent in first and third birth rank (10 cases out of 51 i.e. 19.60%). 86.27% of the cases belong to first four birth ranks (44 our of 51). Maximum number of parents are having five or less than five children (36 out of45 i.e. 68.62% [Figure 1] p value for this distribution is .10.50.

Incidence of colobomatous defect of the globe is highest in second birth rank (27%); next frequency :s in third (20.43%) and then in fourth birth order (17.51%). P value for this distribution i.: P>.0I [Figure 1].

3. Susceptible paternal age group for con�genital cataract is observed to be 31 to 35 years [Figure 2].

Similar maternal age group is 15 to 19 & 24 to 29 years [Figure 3] P value for maternal and paternal age group distribution are .05 .10 and P>.01 respectively.

Susceptible paternal age group for various congenital colobomatous defects of the globe is 26 to 39 years (P>.01); and similar maternal age group distribution is 20 to 30 years (P>.01; [Figure 2][Figure 3]].

 DISCUSSION



Majority of cases of congenital ocular abnormalities are sporadic in occurrence. Heredity and certain environmental factors like X-ray irradiation, certain drugs, viral infection etc. have already been proved to be teratogenic. But very little is known about the biological factors that are responsible for causing congenital abnormalities.

In the process of gametogenesis there is chance of spontaneous genetic or chromo�somal mutation and its frequency in man is about 2 per 1000 births[7] and its chance may be more in the extreme two ends of reproduc�tive age of both members of parents. Biologi�cal competency of the uterus for a normal out-come of a pregnancy is related to mater�nal age and )rarity. Similarly uterine incom�petency causes defective fetal nutrition and subsequent fetal abnormality in some cases.[8] Again fertilization of an over-ripened ovum may give rise to various sporadically occurring congenital abnormalities. In an over-ripened ovum there Tray be chromo�somal scattering or chromosomal maldis�tribution[9] due to low cytoplasmic viscosity. In human being the over ripening of an ovum is possible in late marriage[10] and in long menstruation cycle,[11] which is often found in young and in older ladies.

In the present investigation influence of heredity was found in 8% cases of congenital cataracts and 7.08% cases of colobomatous defects of the globe. Rest of the cases were sporadic. This incidence was a little less than those published in available literature where the incidence is reported to be about 10%.

On certain extra-ocular abnormalities like congenital club foot congenital heart disease and hydrocephalus, studies were carried out by various workers. Few workers found the high incidence of such abnormalities in the children of older mothers and of later birth rank but just reverse report is also available.[12],[13] Nakajima et al[4] reported that less mother in their 20's and more mother in their 30's produce children with microphthalmos and congenital cataract.

We found highest incidence of congenital cataracts amongst children of second birth rank, but it was much less in first, third and fourth birth ranks. The statistical significance for this distribution was .IO.50 [Figure 1]. Similarly highest incidence of colobomatous global defects was found in second birth rank and the frequency drops do-,?,,n gradually from third birth rank onwards which is a highly significant distribution. Murty[3] found highest incidence of cataract and mic�rophthalmos in first and in second and third birth rank respectively.

Mother of third decade and father of 26-39 years age group produce significantly higher number of children with colobomatous ocular defects P>.01 [Figure 2][Figure 3]. Similar sus�ceptible paternal age (P>.0l) for congenital cataract was 31 to 3.5 years and maternal age group was. 15 to 19 and 24-29 years (.05.10). Both of these two distributions are statistically significant. But Nishimura[12] found no statistical relations between birth rank, parental age and congenital abnormalities.

Our clinical investigations and observa�tion of significant co-relation of parental age and birth rank on congenital cataracts and various colobomatous defects of the globe in India gives a further clue for investigation on parental biological factors that are respons�ible for causing various congenital ocular malformations.

 SUMMARY



Influence of birth rank and parental age on congenital cataracts (45 families) and various colobomatous defects of the globe (127 families) were investigated and a statistical analysis on significant co-relation was found between these variables.

 ACKNOWLEDGEMENT



This study is financed by Indian Council of Medical Research.[14]

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