''7p22.1 microduplication syndrome'' (also called ''Trisomy 7p22.1'') is a

genetic disorder 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 chromosome abnormality. Although polygenic disorders ...

which is characterized by cranial and facial dysmorphisms,

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

, and motor-speech delays. It is caused by a duplication of the p22.1 region of

chromosome 7 Chromosome 7 is one of the 23 pairs of chromosomes in humans, who normally have two copies of this chromosome. Chromosome 7 spans about 160 million base pairs (the building material of DNA) and represents between 5 and 5.5 percent of the total DN ...

Signs and symptoms

The symptoms of this syndrome are (but are not limited to) cranio-facial dysmorphisms such as

macrocephaly Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a Heredity, familial genetic characteristic. People diagnosed with macrocephaly will receive further medical ...

frontal bossing Skull bossing is a descriptive term in medical physical examination indicating a protuberance of the skull, most often in the frontal bones of the forehead ("frontal bossing"). Although prominence of the skull bones may be normal, skull bossing may ...

, low-set ears, hypertelorism, etc.,

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

, speech and motor delays, and heart, ocular, renal and skeletal defects (such as

patent foramen ovale Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...

brachydactyly type D Brachydactyly type D, also known as murderer's thumb, stubbed thumb, spoon thumb, or short thumb, is a genetic trait recognised by a thumb being relatively short and round with an accompanying wider Nail (anatomy), nail bed. The distal phalanx of ...

Causes

This condition (as the name implies) is caused by a 430 kB duplication of the p22.1 region of

. This mutation is

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

, meaning that a baby would need 1 copy of a mutated gene from both parents in order to show symptoms of the disorder.

Epidemiology

Only 60 cases of 7q22.1 microduplication syndrome have been recorded in medical literature.

References

{{reflist Genetic syndromes