stetoscopio nella mano di un medico

The syndrome

SDS is a complex congenital anomaly, of hereditary genetic origin, first described in 1964 by Dr Shwachman and Dr Diamond of the Harvard Medical School at Boston Children's Hospital.
The syndrome is a combination of the following conditions:
  • exocrine pancreatic insufficiency (from hypoplasia of the exocrine pancreas);
  • severe bone marrow and blood dysfunctions, mainly neutropaenia (caused by bone marrow hypoplasia).
It is usually associated with short stature, various skeletal disorders and, in some cases, other clinical features.


Hypoplasia of the exocrine pancreas is a congenital developmental defect, affecting the part of the pancreas that produces digestive enzymes. It creates pancreatic insufficiency, resulting in major impairment of digestion and affecting absorption of food. This defect tends to become less pronounced as the child grows, making clinical identification of SDS particularly challenging in older subjects unless sophisticated diagnostic tests are available.

Bone marrow dysfunctions are very varied. Marrow, overall development of which is insufficient, is replaced in part by fatty tissue: this anomaly hinders production of red cells, platelets and the white cells known as neutrophil granulocytes, which normally form the first line of defence against bacteria.

The most frequent defect is neutropaenia, a low neutrophil count, which can be steady-state (always present) but is more often intermittent (meaning that it comes and goes, with no predictable pattern). In addition, the condition generally makes neutrophils sluggish and slows down their arrival at sites of infection. This reduction in the neutrophil count and in their mobility favours infections, especially in very young children, causing earache, bronchopneumonia, osteomyelitis, skin infections and septicaemia.

Thrombocytopaenia (a low blood platelet count) and anaemia (a decrease in red blood cells) occur less frequently.

In very young children, foetal haemoglobin levels are high.

In some cases (frequency still not clearly defined, but low in Italy), myeloproliferation can occur: this means involvement of the bone marrow, with a tendency to develop myelodysplasia or leukaemia - above all, acute myeloid leukaemia.

Short stature is almost always present from birth and is not amenable to correction, even if growth rate is regular.

While bone disorders can be of different types, these are mainly structural alterations affecting the growth plates of large joints (metaphyseal dysplasia of the knee, elbow and hip) or the ribs (narrow rib cage). Valgus knee ("knock knees") can also be present. These alterations, which might be only partly reponsible for the stature deficit, tend to normalise only to a limited degree with age.