What is 9p Minus?
What is 9p Minus?
9p Deletion Syndrome is a very rare chromosome abnormality that reportedly occurs in 1 in 50,000 births.
It is characterized by a portion of the “p” (or short end of the 9th chromosome) being deleted or missing.
The area where chromosome material is deleted is called a “breakpoint.”
Although there are critical regions where breakpoints tend to occur, 9p Deletion Syndrome encompasses deletions anywhere within the “p” end of the 9th chromosome.
The deletion can be a result of a “terminal” deletion where there is a breakpoint and the remaining genetic material to the end of the chromosome is lost, or the deletion can be “interstitial” where genetic material is lost within the chromosome.
This genetic abnormality can occur de novo (randomly without parents being carriers) or as a result of an often healthy parent’s genetic makeup (balanced translocation).
The result of a 9p deletion is a loss genes or genetic material that are normally found within the chromosome.
The size of the deletion often determines how the 9p Deletion Syndrome presents in an individual affected by the genetic abnormality; the larger the deletion, the more pronounced the symptoms are and vice versa.
Unfortunately there is no cure for 9p Deletion Syndrome, but there are many therapies and medical treatments available to assist families and 9pminus individuals.
What’s in a Name?
Since 9p deletions are rare and vary according to breakpoints, there is not a single name given to the disorder.
There are numerous names that describe 9p deletions including 9p- Syndrome, 9p Deletion Syndrome, Alfi’s Syndrome, Monosomy 9p, and other derivatives of the aforementioned names.
Alfi’s Syndrome commonly refers to individuals with a 9p deletion where the breakpoint is found at 9p22.
Other complex 9p Deletions are described as unbalanced translocations (where more than one chromosome “trades” genetic material with another often resulting in lost genetic material), Ring 9 Syndrome (where both ends of the 9th chromosome break and the “sticky” ends fuse thus forming a ring), and a mosaic deletion (where only a percentage of cells are affected).
Physical Symptoms of 9p Deletion Syndrome
Physical characteristics and symptoms can vary greatly, but there are commonly seen attributes among individuals with 9p Deletion Syndrome.
Since the symptoms vary greatly, simply because an individual is diagnosed with a 9p Deletion does not mean they are guaranteed to experience all symptoms associated with 9p Deletion Syndrome.
Trigonocephaly (keel-shaped forehead caused by premature fusing of metopic suture) or minor ridge on forehead
Trigonocephaly is a common feature among individuals with 9p Deletions. For mild cases with a metopic ridge, no treatment is usually necessary. For moderate to severe trigonocephaly, physicians monitor neurological symptoms to determine if surgical intervention is necessary. Some children will undergo helmet therapy to reshape skull.
Choanal atresia (nasal passage narrow or blocked by tissue)
Choanal atresia is rare among individuals with 9p Deletions. Symptoms can include inability to nurse and breath at the same time or repeated one-sided nasal discharge. Surgical correction may be necessary.
Nystagmus (abnormal eye movements)/Strabismus (eyes not aligned)
Flat occiput (flat back of head)
High-arched palate (roof of mouth is higher than normal)
Micrognathia (small, receding jaw)
Midface hypoplasia (upper jaw, cheekbones, eye sockets are undergrown)
Microstomia (small mouth)
Long philtrum (long upper lip)
Upslanting palpebral fissures (corners of eyes upslant)
Low-set, posteriorly positioned ears
Flat nasal bridge
Anteverted nares
Hypertelorism (widely spaced eyes)
Epicanthal folds (skin fold over inner corner of eyes)
Whole Body Features Associated with 9p Deletions:
Globalized hypotonia (low muscle tone)/Delayed gross motor development
Hypotonia is more pronounced at birth but usually improves with age. It delays gross motor development such as sitting, crawling, and walking. It can also affect feeding and swallowing.
Hip dislocations/Highly flexible joints are associated with 9p Deletions and hypotonia. Physicians can monitor for hip dislocations. No treatment is usually necessary for highly flexible joints besides the use of orthotics to reinforce ankle stability.
Seizures: Seizure activity in individuals with 9p Deletions can vary from “staring off in space” to grand mal seizures. Seizures can be present at birth or occur later in life such as with puberty. Treatment of seizures is usually controlled through medications.
GERD (GI reflux)/Delayed gastric emptying
GI reflux and delayed gastric emptying can cause pain, vomiting, and malabsorption of nutrients. Treatment can include medications to treat the reflux and/or to stimulate stomach muscles, dietary changes to promote digestion, tube feedings, and in rare cases, surgical intervention.
Constipation: Constipation is common in individuals with 9p Deletions. Promoting activity, a nutritious and high fiber diet, and the aid of laxatives helps keep stools regular.
Cardiac defects: Often detected at birth, cardiac defects are uncommon but associated with 9p Deletions. Physicians may detect a murmur and/or other cardiac symptoms that initiate further testing.
Frequent infections/Immunocompromised–ear, respiratory
Children with 9p Deletions are prone to infections and often require surgical placement of ear tubes.
Scoliosis (spinal curve)
Scoliosis in individuals with 9p Deletions is related to hypotonia and core strength. Physicians should monitor progression of scoliosis and utilize back braces, casting, and in severe cases, surgery to correct scoliosis.
Kidney reflux: Kidney reflux can be associated with 9p Deletions. Chronic urinary tract infections (UTIs) are the most common symptom. Physicians may order further testing to rule out kidney abnormalities.
Sleep disorders: Sleep disorders are common among individuals with 9p Deletions. Reinforcing a bedtime routine and the use of medications may aid an individual with a 9p Deletion.
Hernias
Long fingers/toes
Narrow feet
Widely spaced nipples
Irregular dental development
Precocious puberty
Abnormal genitalia
Hypopigmentation of skin/hair
Excessive drooling
Glaucoma/Cataracts
Omphalocele (rare)
Cognitive Features Associated with 9p Deletions:
Intellectual disability
Level of cognitive disability varies among individuals with 9p Deletions and is often related to size of deletion.
Speech/Language delay
Mostly all individuals with 9p deletions have a significant speech and language delay. Intensive Speech Therapy is often implemented to aid a child’s language development.
Affectionate, cheery disposition but prone to temper tantrums
Individuals with 9p Deletions are typically viewed as affectionate, warm, and endearing even to strangers. Negative behaviors are not uncommon and can be associated with their inability to verbally express themselves and by not getting their way.
School and Early Intervention for 9p Deletion Individuals
Early Intervention programs including PT (Physical Therapy), OT (Occupational Therapy), and/or ST (Speech Therapy) is often necessary and beneficial for individuals with 9p Deletions.
Most children with 9p Deletions experience a significant delay in reaching developmental milestones
Almost all children with 9p Deletions require PT and OT related to issues with hypotonia. Many individuals with 9p Deletions benefit from AFOs (orthotics or leg braces) to provide gait support. Most individuals with 9p Deletions eventually walk unassisted but some may require a wheelchair for long distances.
Almost all individuals with 9p Deletions require ST to help treat delayed communication. Most individuals with 9p Deletions eventually form language, and many supplement communication with sign language, communication devices, etc. The delay in expressed communication is related to frustration in individuals with 9p Deletions and can lead to tantrums.
Most children with 9p Deletions require special education services through their school system. Some are able to be mainstreamed with additional assistance, and most are taught in a contained classroom.
The majority of children with 9p Deletions require an IEP or certificate of special needs to accompany their schooling. With the family’s direction, the school system’s team of psychologists, teachers, aides, and other personnel create a workable plan to enable the child to thrive in a school atmosphere.
Adulthood in Individuals with a 9p Deletion
Individuals with 9p Deletions require assistance with activities of daily living beyond the age of 18.
Research your rights and responsibilities as a parent or guardian of an individual with a 9p Deletion who is over 18 years of age as laws differ geographically.
Parents need to plan in advance of their child’s 18th birthday to secure a Special Needs Trust, if desired. Several non-profit agencies can assist this process along with an attorney who specializes in this area.