Seckel syndrome
Encyclopedia
The Seckel syndrome or microcephalic primordial dwarfism
(also known as bird-headed dwarfism, Harper's syndrome, Virchow-Seckel dwarfism, and Bird-headed dwarf of Seckel) is a congenital nanosomic
disorder.
Inheritance is autosomal recessive.
It is characterized by intrauterine growth retardation and postnatal dwarfism
with a small head
, narrow bird
-like face with a beak
-like nose
, large eyes with an antimongoloid slant, receding mandible and mental retardation
.
A mouse model has been developed.
3 and 18. One form of Seckel syndrome can be caused by mutation in the gene encoding the ataxia telangiectasia and Rad3 related
protein which maps to chromosome 3q22.1-q24. This gene is central in the cell's DNA damage response and repair mechanism.
Types include:
Primordial Dwarfism
Primordial dwarfism is a form of dwarfism that results in a smaller body size in all stages of life beginning from before birth. More specifically, primordial dwarfism is a diagnostic category including specific types of profoundly proportionate dwarfism, in which individuals are extremely small...
(also known as bird-headed dwarfism, Harper's syndrome, Virchow-Seckel dwarfism, and Bird-headed dwarf of Seckel) is a congenital nanosomic
Dwarfism
Dwarfism is short stature resulting from a medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches , although this definition is problematic because short stature in itself is not a disorder....
disorder.
Inheritance is autosomal recessive.
It is characterized by intrauterine growth retardation and postnatal dwarfism
Dwarfism
Dwarfism is short stature resulting from a medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches , although this definition is problematic because short stature in itself is not a disorder....
with a small head
Head
In anatomy, the head of an animal is the rostral part that usually comprises the brain, eyes, ears, nose and mouth . Some very simple animals may not have a head, but many bilaterally symmetric forms do....
, narrow bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
-like face with a beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
-like nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
, large eyes with an antimongoloid slant, receding mandible and mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
.
A mouse model has been developed.
Genetics
It is supposed to be caused by defects of genes on chromosomeChromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
3 and 18. One form of Seckel syndrome can be caused by mutation in the gene encoding the ataxia telangiectasia and Rad3 related
Ataxia telangiectasia and Rad3 related
Serine/threonine-protein kinase ATR also known as ataxia telangiectasia and Rad3-related protein or FRAP-related protein 1 is an enzyme that in humans is encoded by the ATR gene...
protein which maps to chromosome 3q22.1-q24. This gene is central in the cell's DNA damage response and repair mechanism.
Types include:
| Type | OMIM | Gene | Locus |
|---|---|---|---|
| SCKL1 | ATR Ataxia telangiectasia and Rad3 related Serine/threonine-protein kinase ATR also known as ataxia telangiectasia and Rad3-related protein or FRAP-related protein 1 is an enzyme that in humans is encoded by the ATR gene... |
3q22-q24 | |
| SCKL2 | ? | 18p11-q11 | |
| SCKL3 | ? | 14q | |
| SCKL4 | CENPJ CENPJ Centromere protein J is a protein that in humans is encoded by the CENPJ gene. It is also known as centrosomal P4.1-associated protein .-Further reading:... |
13q12 |
History
The syndrome was named after Helmut Paul George Seckel (American physician, 1900–1960). Harper's syndrome is named after Rita G. Harper.Symptoms
Symptoms include:- mental retardation (more than half of the patients have an IQ below 50)
- microcephalyMicrocephalyMicrocephaly is a neurodevelopmental disorder in which the circumference of the head is more than two standard deviations smaller than average for the person's age and sex. Microcephaly may be congenital or it may develop in the first few years of life...
- sometimes pancytopeniaPancytopeniaPancytopenia is a medical condition in which there is a reduction in the number of red and white blood cells, as well as platelets.If only two parameters from the full blood count are low, the term bicytopenia can be used...
- cryptorchidismCryptorchidismCryptorchidism is the absence of one or both testes from the scrotum. It is the most common birth defect regarding male genitalia. In unique cases, cryptorchidism can develop later in life, often as late as young adulthood. About 3% of full-term and 30% of premature infant boys are born with at...
- low birth weight
- dislocations of pelvis and elbow
- unusually large eyes
- low ears
- small chin