<unk> <unk>  causes a wide range of medical and developmental concerns. As discussed above, people with<unk> <unk>  can have features of both distal<unk> q- and<unk> p-. The features of distal<unk> q- and<unk> p- vary greatly because of the variability of the deletion size and breakpoint locations between people. Because<unk> <unk>  can involve unique deletions of both the p and q arms of the chromosome there is twice as much reason for the variability between individuals. This variation is also partly attributable to the incidence of mosaicism, which is relatively common in people with<unk> <unk> . Septal defect * Holoprosencephaly has been reported in some people with<unk> <unk> . This is due to the deletion of the TGIF gene on the short arm of chromosome<unk>  in some people with<unk> <unk> . Approximately 30-40% of people with<unk> <unk>  have a congenital heart anomaly. Septal defects are the most common type of defect reported in this population. * Hypotonia is frequently seen in the<unk> <unk>  population. Seizures, though uncommon, have been reported in people with<unk> <unk> . * In some children without “classic” holoprosencephaly, microforms of holoprosencephaly may be noted on MRI, including missing olfactory tracts and bulbs and absent or hypoplastic corpus callosum. * Strabismus as well as nystagmus have both been reported in infants and children with<unk> <unk> . * Hearing loss has been reported and may be related to ear canal atresia or stenosis. * Umbilical and inguinal hernias have been reported in a small number of people with<unk> <unk> . * Unilateral renal hypoplasia and aplasia have both been reported in individuals with<unk> <unk> . Hydronephrosis as well as pyelonephritis have also been reported in a few individuals. Cryptorchidism, hypospadias, and micropenis have been seen in males with<unk> <unk> , while females have been reported with hypoplastic labia. * Foot abnormalities are common within the<unk> <unk>  population. Scoliosis as well as pectus excavatum have also been frequently reported. * Several people with<unk> <unk>  have growth hormone deficiency. Hypothyroidism has also been reported in a minority of people. * Cognitive ability varies; according to a literature review, the degree of impairment may fall anywhere between the mild and severe ends of the spectrum. * Facial features of<unk> <unk>  include low-set, dysplastic ears, epicanthic folds, and hypertelorism. Micrognathia has also been reported.
Ring chromosome 18
Ring chromosome 15
Ring chromosome 22
X chromosome
Y chromosome
Dup15q
Distal 18q-
Ethosome