Genetic role of simple hypospadias

Familial aggregation of simple hypospadias is well documented. The inheritance of this disorder was studied in 71 probands and their families up to the third degree relatives [1107 males] using X2 test for autosomal dominant inheritance and sib-method for autosomal recessive inheritance. An estimation of heritability, a test for multifactorial inheritance, parental consanguinity and average coefficient of inbreeding were done. The results revealed that a higher frequency of the disorder was found among relatives of the probands and diminished as the degree of relationship descended. Data was inconsistent with monogenic modes of inheritance in spite of high consanguinity rate and average coefficient of inbreeding. The results agreed with the multifactorial inheritance. The estimated weighted mean of h2 was 78.08% indicating the importance of the genetic role in the etiology of uncomplicated hypospadias

Genetic study of microcephaly; syndromal and non syndromal

This study included 100 patients suffering from microcephaly, from those attending the Genetic Clinic, Medical Research Institute, Alexandria University. They were subjected to complete genetic, family, pregnancy and delivery history, pedigree analysis, anthropometric measurements, clinical genetic examination, chromosomal analysis, X-rays and other investigations [CT, ophthalmological examination, EEG]. The results revealed that 38 patients had non syndromal microcephaly [52.6% isolated cases and 47.4% familial]. The estimated sib recurrence risk for isolated microcephaly was 20%. Several varieties of autosomal recessive microcephaly were found with a high frequency of microcephaly with seizures and spasticity [50% and 44% in isolated and familial cases respectively]. Syndromal microcephaly included 62 patients. Out of these, 40 had single gene disorders 14 [35%] had autosomal dominant syndromes, 22 [55%] had autosomal recessive and 4 [10%] had X-linked recessive [XLR] syndromes. Seventeen patients had chromosomal abnormalities with 70.5% due to numerical aberrations and 29.5% had structural defects. Four patients were microcephalic due to environmental exposure to infections and one secondary to craniosynostosis. The high frequency of consanguinity [72%] and estimated sib recurrence risk reflect the high contribution of autosomal recessive microcephaly and syndromes in this study

Malformations in infants of diabetic mothers

Among 266 infants of diabetic mothers [IDM] were examined, 14 showed malformations. They were subjected to careful pregnancy, delivery and family history complete clinical genetic examination and other investigations [chromosomal study. X-rays, ultrasound and ECG]. The results revealed that congenital heart disease was found in 5/14 neural tube defect in 2/14, femoral hypoplasia, unusual face with cleft palate in 2/14, congenital hip dislocation in 2/14. polycystic kidney in 1/14, caudal regression in 1/14 and one patient had microcephaly and skeletal anomalies. Rigid metabolic control of the maternal diabetes at the time of conception is suggested to reduce the malformation in IDM