Morocco, screening for MYH mutations should be considered in young patients presenting with spo­radic colorectal cancer, even with a limited number of adenomas. A variable number of polyps (ranging from five to 100) and early onset colorectal cancer; absence of vertical transmission from parent to off­spring, sporadic or multiple-case presentations with­in one generation, are characteristic of an autosomal recessive pattern of inheritance [5] and represent a clinical-genetic picture of MAP. This observation is similar to those described in previous studies [3,6,7] and confirms that MYH mutations are not frequent in the general population [8].

In Morocco, consanguineous marriage is cultur­ally favored and is an integral part of the country's cultural and social life. The high rate of consanguin­ity (15.25%) explains the prevalence of autosomal recessive diseases in the country [9]. Therefore, we expect that MAP may be more common in this country than in developed countries. This consider­ation should be integrated in any colorectal cancer surveillance program.

In conclusion, patients with a classical or atten­uated form of polyposis coli should be screened for MYH mutations. Identification of MYH mutations has important implications for the diagnosis, screen­ing, genetic counseling, follow-up and therapeutic options in patients with colorectal cancer. Gene test­ing should identify siblings of MAP cases who are at risk and clarify the genetic status of spouses of those with biallelic mutations, so that their offspring can be counseled.