Conradi–Hünermann syndrome is a rare type of chondrodysplasia punctata. It is associated with the EBP gene and affects between one in 100,000 and one in 200,000 babies.

Signs and symptoms

Possible signs and symptoms may include

Genetics

Conradi–Hünermann syndrome is a form of chondrodysplasia punctata, a group of rare

genetic disorders A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...

of skeletal development involving abnormal accumulations of calcium salts within the growing ends of long

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

s. Conradi–Hünermann syndrome is commonly associated with mild to moderate growth deficiency, disproportionate shortening of long bones, particularly those of the upper arms and the thigh bones, short stature, and/or curvature of the spine. In rare cases,

intellectual disability Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signif ...

may also be present. While evidence suggests that Conradi–Hünermann syndrome predominantly occurs in females and is usually inherited as an

X-linked dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type ...

trait, rare cases in which males were affected have also been reported. The genetics of Conradi–Hünermann syndrome have perplexed medical

geneticists A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic processes ...

pediatricians Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the ...

and

dermatologist Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medica ...

s for some time, but a number of perplexing features of the genetics of the syndrome have now been resolved, including the fact that the disease is caused by mutations in a gene, and these mutations are simple substitutions, deletions or insertions and are therefore not "unstable". Scientists are still trying to understand exactly where the mutation occurs so that they can correct it.

Diagnosis

An important test to confirm a diagnosis of Conradi-Hünermann syndrome is evaluating the plasma for elevated levels of a substance known as sterols. Mutations of the EBP gene result in the accumulation of sterols in the plasma and certain tissues of the body. Sterol levels are measured by gas chromatography- mass spectrometry.

Screening

Genetic screening for Conradi-Hünermann syndrome via the EBP Gene is offered by multiple providers.

Treatment

Treatment can involve operations to lengthen the leg bones, which involves many visits to the hospital. Other symptoms can be treated with medicine or surgery. Most female patients with the syndrome can live a long and normal life, while males have only survived in rare cases.

History

It is also known as Happle's syndrome, after the German Physician, Rudolf Happle (b. 1938), who wrote a series of papers about the disease in 1976. The name Conradi-Hünermann Syndrome is named for Erich Conradi (1882–1968), and Carl (Karl) Hünermann (1904–1978), both are German Physicians.

References

External links

GeneReviews/NCBI/NIH/UW entry on Chondrodysplasia Punctata 2, X-Linked, Conradi–Hünermann Syndrome, Happle Syndrome
{{DEFAULTSORT:Conradi-Hunermann syndrome Genodermatoses Skeletal disorders Syndromes affecting the skin Cholesterol and steroid metabolism disorders Rare syndromes