The Clinical Phenotypes of Alpha Thalassemia

The effect of red blood cell disorders on male fertility and reproductive health

Male infertility is defined as a failure to conceive after 12 months of unprotected intercourse owing to suspected male reproductive factors. Non-malignant red blood cell disorders are systemic conditions that have been associated with male infertility with varying severity and strength of evidence. Hereditary haemoglobinopathies and bone marrow failure syndromes have been associated with hypothalamic-pituitary-gonadal axis dysfunction, hypogonadism, and abnormal sperm parameters. Bone marrow transplantation is a potential cure for these conditions, but exposes patients to potentially gonadotoxic chemotherapy and/or radiation that could further impair fertility. Iron imbalance might also reduce male fertility. Thus, disorders of hereditary iron overload can cause iron deposition in tissues that might result in hypogonadism and impaired spermatogenesis, whereas severe iron deficiency can propagate anaemias that decrease gonadotropin release and sperm counts. Reproductive urologists should be included in the comprehensive care of patients with red blood cell disorders, especially when gonadotoxic treatments are being considered, to ensure fertility concerns are appropriately evaluated and managed.

Genetic epidemiology of thalassemia in couples of childbearing age: over 6 years of a thalassemia intervention project

BACKGROUND

Shenzhen is one of the most populated metropolises in southern China where thalassemia is highly prevalent. The prevention of thalassemia inheritance is an ambition of child-bearing couples.

METHODS AND RESULTS

A total of 22,098 peripheral blood samples were collected from 11,049 potentially at-risk couples of childbearing age from Shenzhen. Thalassemia mutations were determined by PCR-based flow-through hybridization. The results identified 45.02% of the participants (9948 out of 22,098) as harboring globin gene mutations, distributed into 18 α-thalassemia alleles detected in 71.48% (7111 out of 9948) and 15 β-thalassemia alleles detected in 32.68% (3252 out of 9948) of all mutant individuals, among which 415 individuals carried both α- and β-thalassemia alleles. The most frequent phenotypes for α-globin variations were --SEA/αα (63.37%), -α3.7/αα (18.66%), and -α4.2/αα (7.31%), and those for β-globin variations were β41-42/βN (34.96%), β654/βN (28.11%), and β17/βN (13.84%). A total of 970 high-risk couples who could possibly give birth to offspring with thalassemia intermedia or major were identified. In addition, the hematological indices were compared among thalassemia genotypes. Significant differences in MCH, MCV, Hb A, and Hb A2 levels among α-thalassemia minor (α+), trait (α0), and intermediate phenotypes (P < 0.05) and between βE/βN and the other β-thalassemia phenotypes (P < 0.05) were found. Moreover, GAP-PCR and next-generation sequencing further identified 42 rare mutations, 13 of which were first reported in the Chinese population. A novel mutation in the β-globin gene (HBB: c.246 C > A (rs145669504)) was also discovered.

CONCLUSIONS

This study presented a comprehensive analysis of thalassemia variations in a population from Shenzhen and may offer valuable insights for thalassemia control and intervention strategies in this area.

The Spectrum of α-Thalassemia Mutations in Syrian Patients

α-Thalassemia (α-thal) is a globally prevalent genetic disorder of hemoglobin (Hb) structure where the rate of α-globin chain synthesis is reduced or absent due to the presence of α-globin mutation(s). The aim of this study is to define the spectrum of α-globin gene mutations and evaluate their allele frequency in a group of α-thal carriers. A total of 55 individuals with possible α-thal patients were referred from the thalassemia centers in Syria. They have unexplained hypochromia and microcytosis. All patients were genetically tested for 21 common α-globin gene mutations using reverse hybridization kit. Seven different α-globin gene mutations and 13 different genotypes were detected in 55 patients. The two most frequently encountered mutations were -α3.7 deletion (47.1%) and --MED mutation (21.4%). The most commonly observed genotype was -α3.7/αα (40%), followed by --MED/αα genotype (21.8%). We determined the most common α thalassemia mutations in the Syrian patients. α-Thalassemia mutations with deletions were mostly observed in our study.