Shwachman-Diamond Syndrome

Shwachman-Diamond Syndrome (SDS) is an autosomal recessive disorder with an incidence of 1 in 50,000 births. SDS affects many organs in the body and the symptoms may vary from individual to individual. The primary features of SDS include: bone marrow problems (leading to inadequate production of some types of blood cells), a defect in the pancreas (leading to difficulties in digesting food), skeletal abnormalities, and short stature. Other, secondary, features may affect some but not all people with SDS. People with SDS are at risk for serious, sometimes fatal, complications such as severe infections, bone marrow failure and acute myelogenous leukemia.

The SBDS gene at 7q11 has recently been found to be the causative gene for SDS A pseudogene, SBDS-P, exists within a distally duplicated region and shares 97% nucleotide sequence identity with the SBDS gene. A majority of SDS patients have mutations resulting from recombination and gene conversion between the SBDS and SBDS-P genes. The two common conversion mutations account for 75% of all SDS disease alleles.

The disease is present when a child receives two copies of a defective gene, one from each parent. Any person with one copy of the defective SDS gene is a SDS carrier. Carriers do not have, and will never develop, SDS. However, if two carriers wish to have children, there is a one in four chance (25%) that their baby will be born with SDS. There is a three in four chance (75%) that their baby will not have SDS.

See related information sheet: Shwachman-Diamond Syndrome