Seckel syndrome
Synonyms and keywords: Bird-headed dwarfism; Harper's syndrome; microcephalic primordial dwarfism 1; nanocephalic dwarfism; Seckel-type dwarfism; Virchow-Seckel syndrome

# Overview
The Seckel syndrome or microcephalic primordial dwarfism is a congenital nanosomic disorder supposed to be caused by defects of genes on chromosome 3 and 18. It is characterized by intrauterine growth retardation, along with growth & developmental delays even after birth. There are characteristic bird like facies with a beak like nose, microcephalic head, micrognathia(small head) and malformed ears.  One form of Seckel syndrome can be caused by mutation in the gene encoding ataxia-telangiectasia and RAD3-related protein ATR which maps to chromosome 3q22.1-q24.

# Historical Perspective
The syndrome was named after Rudolf Virchow and Helmut Paul George Seckel (American physician, 19001960). The condition was named by R Virchow but the first accurate description was given by Helmut Seckel in 1960, who originally described the condition based on 2 actual cases that he saw and 11 other reported cases of nanocephalic dwarfs over a period of almost 200 years!!

# Classification
The classification is based on the gene locus carrying the specific mutation.
- SCKL1 casued by mutation in ATR gene on chromosome 3q22.1-q24
- SCKL2 by RBBP8 gene on chromosome 18q11
- SCKL3 on chromosome 14q
- SCKL4 by CENPJ gene on chromosome 13q12
- SCKL5 by CEP152 gene on chromosome 15q21
- SCKL6 by CEP63 gene on chromosome 3q22  and
- SCKL7 by NIN gene on chromosome 14q22.

# Genetics
Seckel Syndrome is caused primarily by a homozygous or a compound heterozygous mutation in a gene encoding ataxia-telangiectasia and RAD-3 related protein ATR located on chromosome 3q22.1.q24.. This gene is central in the cell's DNA damage response and repair mechanism. It is an autosomal recessive mutation. There are several other minor mutations that are associated with the disorder.

# Associated Conditions
There is a group of disorders which are associated with primordial dwarfism. These disorders share overlapping features and need to be put into consideration for all cases of genetic dwarfism's. Seckel Syndrome being one of them. The others included in this group are:
- Ear patella short stature
- Russell Silver syndrome
- Majewski osteodysplastic bird head dwarfism type I/III and
- Majewski osteodysplastic bird head dwarfism type II

# Epidemiology and Demographics
It is an extremely rare disease, with just over a 100 cases being reported all over the world, since its original description in 1960. It affects males and females equally. However a few groups have challenged a number of reported cases and the actual number might be well below 100.

# Screening
The advent of ultra-sonography and its widespread use in pre-natal screening has made it possible to identify Seckel syndrome prenatally.

# History
A directed history and pertinent physical examination should be done to obtain following signs & symptoms:
- Low birth weight(Intra uterine growth retardation)
- Postnatal Dwarfism resulting from growth retardation and delayed bone maturation.
- Cranio-Facial abnormalities comprising of:
- Microcephaly
- Small chin
- Unusually large eyes
- Micrognathia (small jaw)
- Beak like nose, low ears etc.
- Achondroplasia
- Cryptorchidism
- Dislocations of pelvis and elbow
- Pancytopenia
- Mental retardation mild to moderate.
- Other skeletal abnormalities such as clinodactyly (fifth finger fixatedin a bend position permanently) and clubfoot are sometimes seen.

# Treatment
Growth retardation associated with Seckel syndrome shows some response to growth hormone therapy if started early into the natural history of the disease. 
. Many other hematological abnormalities are associated, such as pancytopenia, anemias, leukemia and are treated as they arise.