Kagami-Ogata syndrome
Kagami-Ogata syndrome is a rare genetic disease that is caused by mutations on maternal chromosome 14 or by paternal UPD. The main signs of this disease are: polyhydramnios, narrow bell-shaped thorax, coat-hanger-like ribs, abdominal wall defect, enlarged placenta. Patients with KOS also have a facial dysmorphism, such as: frontal bossing, excessive hair growth on forehead, depressed nasal bridge, micrognathia with/or retrognathia, full cheeks, webbed neck, protruding philtrum.
Symptoms
The symptoms of this disease are:Very frequent:
- Anteverted nares
- Bell-shapes thorax
- Protruding Philtrum
- Coat hanger-like ribs
- Depressed nasal bridge
- Dysphagia
- Full cheeks
- Intellectual disability
- Enlarged placenta
- Joint mobility limitation
- Micrognathia
- Webbed and short neck
- Respiratory failure
- Polyhydroamnios
- Puckered lips
- Coxa valga
- Small eye openings
- Frontal bossing and hirsutism
- Premature birth
- Omphalocele
- Kyphoscoliosis
- Anomalies of the cardiovascular system
- Hepatoblastoma
- Overgrowth
- Postnatal growth retardation
- Seizures
Cause
There are three main mechanisms that can cause KOS:- Paternal Unipaternal Disomy. This can be caused by monosomy rescue. Usually Paternal UPD arises from nondisjunction in oocyte which causes nullisomy of that chromosome. When such oocyte gets fertilised, conceptus will have 1 chromosome and autosomal monosomy is fatal most of the times. In monosomy rescue, chromosome gets duplicated and it can cause problems in gene expression pattern.
- Epimutation on maternal chromosome 14. Epimutation doesn't affect DNA, but rather by gene expression by chemical interactions. In that case genes on maternal chromosome 14 gets methylated and subsequently deactivated.
- Deletion of 14q32.2. In that case part of the maternal chromosome 14 gets deleted.