Screening immediate family members for carrier identification and counseling: a cost-effective and practical approach

To screen immediate family members of thalassaemia patients for carrier identification and counselling.

The cross-sectional study was conducted at an urban thalassaemia treatment and prevention centre in Karachi, Pakistan, from January to December 2008, and involved 188 siblings of 100 thalassaemia patients. Complete blood count, including haemogram, was performed in the siblings. Samples with MCV < 75fl and MCH < 25% were subjected to haemoglobin-electrophoresis. Haemoglobin A2 of 3.5% to 7.0% was labelled as beta-thalassaemia minor. Those with haemoglobin A2 of 3.0-3.4% but red blood cell count of > 4.5 x 1012/L were reported as equivocal and were screened for iron deficiency anaemia and a repeat haemoglobin A2 estimation was done on high performance liquid chromatography. Equivocal results of the chromoatography were screened for thalassaemia mutation. Mean values along with standard deviation were worked out for relevant variables.

Of the 188 subjects, there were 124 (66%) males and 64 (34%) females. The mean age was 16.5 +/- 6.3 years (range: 3 months to 30 years) and the mean family size was 1.88 +/- 3.8 (range: 1-12) children per family. There were 51 (51%) first-cousin marriages in this group. Of the siblings, 65 (34.5%) were identified as normal, while 117 (62.2%) were reported as beta-thalassaemia carriers. Six asymptomatic siblings were reported as consistent with beta-thalassaemia major.

There were 62.2% siblings identified as beta thalassaemia carriers in the study as opposed to 5-8% carriers in the general population. We also identified six asymptomatic and unidentified cases of beta-thalassaemia intermedia in these families. Therefore, in our context where both resources and budgets are limited, it is practical to focus on siblings of identified thalasaemia patients.