The current investigation shows a relatively equal sex ratio in the participants with respect to sex (52% males and 48% females). This slight male predominance parallels that observed in several local studies in Najaf province where a marginal higher rate of genetic blood diseases was recorded among males, of which thalassemia is the most common. For instance, Al-Hakim et al. (2020)], 53.437% of genetic blood disorders patients in their study were males. Furthermore, with the symptoms of the disease presenting themselves females in some families were visited at hospital comparatively less when comparing with males. This ignorance may further cause a late diagnosis or less tendency of healthcare-seeking behavior for female patients. Mikael and Al-Allawi (2018) also found that socio-cultural -preserving factors were affecting pre-diagnosis and PCC among Iraqi females.
The incidence was highest in children aged between 1and 5 years (31.1%) and 5 and 10 years (29.3%). This is consistent with previous studies that have reported severe presentations to occur during early childhood (Mikael & Al-Allawi, 2018). The lower rates among older patients probably reflect better survival with habitual transfusion therapy.
The distribution of study participants on the basis of their place of residence is presented in Figure It indicates that 64% were from urban and 36% came from rural. Part of these results are in line with the study by Al-Hakim et al. (2020) who found that the majority of patients suffering from hereditary blood diseases in Najaf were living in the city center 56.42% then rural areas in other townships in the governorate. However, Ali and Abdulla (2022) found 60% of their sample with thalassemia major patients were from rural areas. The discrepancy in the distribution of thalassemia and other related genetic blood disorders reported here stresses that the geographical distribution of thalassemia and other hereditary defects will vary among studies based on study population, sampling procedures, and demographic diversity within a particular governorate.
The frequency of ABO blood group of the samples are shown in (figure 4) with blood type O (35%) being most common, followed by types A (32%), B(27%) and AB(6%). This distribution suggests an over representation of blood group O in thalassemia patients in Najaf. To the best of our knowledge, this distribution might not represent ABO blood group pattern in people residing in Najaf Governorate or even for Iraqis as a whole. It has been reported by various studies that blood groups differ with respect to geographic region and ethnic races. In population based-studies in Iraq, blood group O was most common followed by A and then B, while AB is the least common. This observation is consistent with the result of Hassan (2016) but contrasts the conclusion obtained by Abid and Ereiby (2019). This could be attributed to variations in the study population, sample size, regional demographics and genetic factors responsible for distribution of blood group.
The distribution of the Rh factor among the studied patients is shown in Figure (5) which indicates that most of the patients were Rh positive (92%) and only 8% were Rh negative. In the current research, these results show that most of the patients with thalassemia are Rh positive and this is consistent with the distribution of Rh factor in general Iraqi population. Rh positive Iraqis account for 85–95% of population (Mohssin and Mahmood 2015).
There is no direct evidence supporting a causal association between the Rh factor and thalassemia, as thalassemia is a hereditary disorder resulting from mutations in hemoglobin genes, whereas the Rh factor is determined by an entirely different genetic system. Therefore, the high prevalence of Rh-positive individuals among thalassemia patients merely reflects its predominance in the general population and does not indicate that the Rh factor represents a risk factor for the development of thalassemia.
Figure (6) illustrates the rate of consanguinity in patients' parents. Results: We revealed that the percentage of patients with consanguineous parents was 83%, and that of patients with nonrelated parents was 17%. This result illustrates a very high prevalence of consanguinity in thalassemia patients' families in Najaf; hence the possible role of consanguineous marriage in increasing the risk of genetic disorders like thalassemia. The high proportion of thalassemia (83%) compared to other spectrum of genetic disease (consanguineous marriage being established as causing rise in both autosomal recessive genetic disease) strongly supports the scientific literature that clearly indicates the prevalence of autosomal recessive genetic disorder in the offsprings of consanguineous marriages. This increases the likelihood that a child will inherit both recessive alleles that cause the disease. Such practical implications from the findings highlight the need for health education and creativeness in plans and giving presentations for local community awareness concerning the risks of consanguineous marriage and its contribution to the incidence of genetic disorders. Such a result reinforces the findings reported by Al-Hakim et al. (2020).
Distribution of thalassemia patients as per the number of affected siblings in the same family, representing interfamilial inheritance (Figure) From the results, 90% of patients had one or more affected siblings and only 10% of patients had all their unaffected siblings. Families with one affected sibling had the second highest proportion (25%), followed by two affected siblings (21%), three affected siblings (33%), and four affected siblings (11%). These results corroborate the autosomal recessive nature of thalassemia, as the disease occurs when an individual inherits impaired thalassemia alleles from both parents. When marriages are consanguineous, the probability that both parents carry the same recessive gene is much higher, as is the proportion of affected children in a family. The large percentage of families with more than one sibling affected especially those with three or more (44%) highlight the immediate need for premarital genetic screening and the advent of early diagnosis programs to prevent new cases from being born. These findings are in accordance with the previous studies (
The character of shows the types of thalassemia in the sample under study (figure 8). Results also demonstrated that thalassemia major was the most common, contributing 68%, thalassemia minor 32%. This result shows that most patients in the sample have the more advanced (more severe) form of the disease. These findings are similar to the results obtained from the study conducted by Mikael and Al-Allawi (2018), where a higher percentage of people with thalassemia major were higher. Thalassemia major is considered the more serious form which usually requires repeated blood transfusions and more intensive medical management, while thalassemia minor usually has little or no clinical symptoms.