12q14 microdeletion syndrome or osteopoikilosis-short stature-intellectual disability syndrome is caused by heterozygous deletion at the region of 12q14. The microdeletion affects the LEMD3 gene which has already been implicated in osteopoikilosis.
Epidemiology
Prevalence is <1 in 1 million live births. Whilst usually a spontaneous/de novo mutation, in <1% of cases both parents may have normal chromosomes noted on blood tests but few of their sperm or eggs carry the microdeletion. This would result in germline mosaicism and their subsequent children may have the same microdeletion. If inherited, it is passed on in a dominant pattern and the possibility of having another child with the microdeletion is up to 50% with each pregnancy (regardless of gender).
Clinical presentation
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pregnancy
usually no detectable antenatal features on ultrasound assessment
rare reports of intrauterine growth restriction (IUGR), oligohydramnios
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neonatal
feeding difficulties/failure to thrive
hypotonia that may contribute to poor latching
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development
small for dates likely due to poor feeding
fine motor skills development have been reported, longer to grasp items or dress/feed themselves
delay in language development, learning difficulties
Other features include
osteopoikilosis: can be absent at birth and only develop in teenage years
irregular marks or lesions: yellowish areas of skin, increased pigmentation
cardiac pathology: VSD, ASD, PDA, hypertension, pulmonary stenosis
extremities: clinodactyly, joint laxity, single palm crease, large thumbs, short broad fingers
dental: late eruption of teeth
ocular: some reports of strabismus. hypermetropia
other: middle ear effusion requiring grommets, ectopic kidneys. scoliosis
neurodevelopmental: attention deficit hyperactivity disorder, autism spectrum disorder