Primordial Dwarfism

What does the name mean?

Primordial has been defined as belonging to or being characteristic of the earliest stages of development of an organism. Therefore, Primordial Dwarfism is a class of disorders where growth delay occurs at the earliest stages of development. Unlike some of the other forms of dwarfism where newborn infants can have average lengths, children with Primordial Dwarfism are born smaller than average and have intrauterine growth retardation (IUGR).

What conditions make up the class of primordial dwarfism?

Unlike some of the other specific conditions described on this website, primordial dwarfism is not a specific diagnosis. It is in fact a class of disorders to which at least 5 different conditions are currently grouped: Russell-Silver syndrome, Seckel syndrome, Meier-Gorlin syndrome, and Majewski osteodysplastic primordial dwarfism (MOPD) Types I/III and Type II. The Russell-Silver, Seckel and Meier-Gorlin syndromes are relatively well defined entities and we will not discuss them here. We will limit our discuss to MOPD Type II. Most of the information below can be examined in more detail in Hall et. al (1).

How common is primordial dwarfism?

All of the conditions are quite rare and very little is known concerning the incidences. For MOPD Type II, we estimate that there are no more than 100 patients in the United States and Canada giving a rough estimate of 1 in 3 million.

Is MOPD Type II inherited?

The precise gene and inheritance pattern of MOPD Type II is unknown, but most data suggest that it follows an autosomal recessive pattern. There are several sibling pairs born to parents of average stature.

What causes MOPD Type II ?

The underlying cause is unknown.