Which of the following is not a hereditary disease?

The correct option is A Cretinism
Cystic fibrosis is caused by mutation in CFTR gene, present on long (q) arm of chromosome 7 which codes for chloride channels.

Thalassemia are a group of blood disorders which are caused by abnormal synthesis of hemoglobin that result from mutations in the HbB and HbA genes present on chromosome 11 and chromosome 16 respectively.

Haemophilia is a genetic disorder because the governing genes are present of X-chromosome. The trait is transmitted to offspring in a sex linked manner from mother to son and from father to daughters.

Cretinism is characterized by stunted physical and mental growth and is caused due to untreated genetic deficiency of thyroid hormones. It is not inherited from parent to offspring.

Thus, the correct answer is option A.