Genealogic study in down syndrome

Genealogies of 66 child with trisomy 21 [Down Syndrome] as diagnosed by chromosome analysis were constructed. The control group included 198 child [three controls for each patient] with no apparent genetic pathology matched in age and sex with the patients. Genealogies of the controls were also constructed, the frequency of consanguineous marriages and average breeding coefficient in parents and grandparents of patients and controls were determined. Parental consanguinity and inbreeding coefficient showed non significant increase in patients than in control. Significant increase in the frequency of consanguinity and in inbreeding coefficient was found only in maternal grand parents of Down patients. Positive family history of Down syndrome in the relatives of the mother's patient was found. The results may suggest that consanguinity has some association with the occurrence of Down syndrome. Homozygosity of autosomal recessive gene may prevent the loss of the trisomic fetus. In addition, the results strengthen the suggestion that homozygosity for autosomal recessive gene may be a predisposing factor to meiotic nondisjunction in mothers who are the offspring of consanguineous parents

Down syndrome and maternal age: changes over time and review of risk factors

During 1987-1996, 292 Egyptian Down syndrome [Trisomy 21] infants were identified in Human Genetics Department in Alexandria. They comprised 139 males and 153 females [sex ratio 0.91]. Data on maternal age, paternal age and birth order were analyzed. Maternal ages were examined for transient changes over time and for linear trends. Significant changes in maternal age over the 10 years period of study were observed. First born infants were at greater risk of trisomy 21 than higher order of births, independent of maternal age

Genetic study of epilepsy

This study comprised 32 patients with epilepsy. They were referred to the Human Genetics Department, Medical Research Institute, Alexandria University, Egypt. They were mentally retarded with the exception of three patients who had normal mentality. Their ages ranged from 2 months to 16 years. Females and males were equally affected [M/F = 1]. All patients were evaluated to identify the specific etiology of epilepsy. They were classified into symptomatic generalized epilepsy [29 cases] and idiopathic generalized epilepsy [3 cases]. After evaluation they were classified according to their diagnosis into those displaying mendelian inheritance, nonmendelian inheritance and chromosome disorders. The symptomatic group showed a mendelian inheritance and chromosomal aberrations while the idiopathic group showed a nonmendelian inheritance

Chromosome anomalies in normal androgenized infertile males

Chromosome anomalies are known to play a role in human infertility. Chromosome analysis of 103 normal androgenized infertile azoospermic [97.1%] or oligospermic [2.9%] males revealed that the frequency of chromosomal abnormalities was 8.7%. Two patients [1.94%] had a 46,XX chromosome complement, one patient [0.97%] had a 45,X karyotype, two patients [1.94%] had a 45,XY,t[13;14][p11;q11] karyotype, one patient [0.97%] had a 46,XY,inv[9][p12;q13] chromosome constitution, two patients [1.94%] had a 46,XY,del[Y][q12] karyotype, and one patient [0.97%] had a 45X/46,X+marker the nature of which was not clarified

Genetic study of phenylketonuria

Among four hundred and eighty mentally retarded patients referred to the Human Genetics clinic, Medical Research Institute, Alexandria University, Egypt; twelve cases were found to have pku, ten cases had classical pku and 2 cases atypical pku. Genetic studies of those patients and their families revealed segregation of autosomal gene [s] that are responsible for the development of the disorder with a recurrence risk of 0.283 +/- [1.96] [0.066]. The high average inbreeding Coefficient indicated the important role played by consanguinity. Heterozygote detection is very important to normal sibs of affected patients to provide proper genetic counseling. Dietary management of the young infants in the first three months showed normal growth and development. Behavioral improvement was observed in cases who were treated late despite the fact that they were mentally retarded. Dietary control should be continued for a long life time to obtain good outcome in both sexes and to prevent the risk of fetal damage during child-bearing age in females