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Majewski Osteodysplastic Primordial Dwarfism Type II

Also known as: MOPD II

Background

Majewski osteodysplastic primordial dwarfism type II (MOPD II) is a form of primordial dwarfism, which is the name given to a group of disorders where undergrowth occurs in the womb. Babies with one of the primordial dwarfism disorders are smaller than average size at birth. It is thought that MOPD II affects about 1 in 3 million people. It occurs equally in male and females and in all ethnic groups.

Credits

Last reviewed July 2016 by Professor J Hall, Professor Emerita of Pediatrics and Medical Genetics, Department of Pediatrics, British Columbia Children's Hospital, Vancouver, Canada.

What are the symptoms?

The features of MOPD II include:

  • low birth weight at full-term delivery, typically under 1kg (2.3lbs) and with a length in the range of 40cm (16")
  • microcephaly
  • a prominent nose
  • dental anomalies, including very small and missing teeth
  • scoliosis and kyphosis (outward curvature of the chest area of the spine) may occur in later childhood
  • relative shortening of the forearm
  • dislocation of the hip (see entry Developmental Dysplasia of the Hip) and bowing of the knees, which may lead to dislocation of the knees
  • sparse and fine hair in some children
  • skin may develop blotchy pigment in sun exposed areas
  • in adulthood, a typical height of less than 1m (39")
  • precocious puberty (see entry Premature Sexual Maturation) in some girls
  • farsightedness (also known as long-sightedness) in some children - where objects can be seen clearly at a distance, but objects nearby may be blurry
  • renal (kidney) structural abnormalities are found in some children
  • aneurysms (small out pouching of the blood vessels in the head) which may lead to a person being more likely to have stroke-like episodes (see entry Stroke). These episodes are a common feature of Moyamoya syndrome.

What are the causes?

MOPD II is a very rare inherited condition. The gene for MOPD II has been identified as PCNT on chromosome 21. It is a mutation (change in DNA) in this gene that causes MOPD II.

How is it diagnosed?

Diagnosis is made by observation of the clinical features, X-ray, family and medical histories and by molecular testing (DNA testing) looking for the genetic mutation in PCNT. Aneurisms (small out pouching of the blood vessels of the brain) can be diagnosed by a cerebral angiography (a test in which a dye is injected into the arteries of the brain to show up problems).

How is it treated?

There is no cure for MOPD II and treatment is designed to help reduce the symptoms. Many children with MOPD II have feeding problems and can benefit from help such as frequent feeding with small amounts and, in some cases, with naso-gastric feeding (through a tube to the stomach). Growth hormone does not help.

Monitoring of the following is required:

  • the eyes for the development of farsightedness
  • the kidneys for renal anomalies
  • the cerebral vascular system for any indication such as Moyamoya syndrome and the possibility of stroke.
  • the small teeth require regular dental monitoring
  • use of sunblock when the affected person is exposed to the sun because of skin fragility.

Equipment and advice may need to be sought to aid with daily living tasks for somebody with short stature. In some cases, orthopedic or psychological support may also be necessary.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
The mode of inheritance is autosomal recessive.

Prenatal diagnosis
This is possible via amniocentesis or chorionic villus sampling, once the specific mutation is identified in a family.

Is there support?

Walking with Giants Foundation

Tel: 0151 526 0134
Email: via website
www.walkingwithgiants.org

The Foundation is a Registered Charity in England and Wales No. 1123246. It provides information and support for individuals affected by Primordial Dwarfism, and their families and carers. The Foundation helps individuals and families to meet others and offers assistance with adaptive and medical needs.

Group details last updated July 2016.

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