2q37 Deletion Syndrome (Chromosome 2)

When Victoria was first diagnosed with 2q37 deletion syndrome (chromosome 2), I did some research, but we were not having any major problems, outside of her developmental and scholastic delays. Since she has been starting to go through puberty, I have noticed some changes in her social skills and I have done some more research. A lot of the following I remember, but some was a refresher. Although I did not find anything that would help me to build her social skills, I was able to locate a group and have asked to join them to possibly speak with other families. The name of the group is "Unique - The Rare Chromosome Disorder Support Group". I will let you know how things turn out with them when I hear back from them!

My last post was similar to the post below, but I have highlighted in red bold italics the features that Victoria has either dealt with in the past or is dealing with currently below... This is primarily for Victoria's family and friends to get a better understanding of her disorder.

2q37 Deletion

2q37 deletion syndrome is an emerging chromosome condition. People with the syndrome have lost a small amount of genetic material (DNA) from the end of one of their two chromosome 2s and this affects their development. However, exact breakpoints vary and even when they are the same, a striking variability is a hallmark of 2q37 deletion syndrome. Even family members with exactly the same amount of lost chromosome material can be very differently affected, although the affects of the syndrome are usually seen in the same areas of development. In this chromosome condition more than others, the individuals other genes, their personality, home environment and the opportunities and experiences offered to them will help to shape their future development, needs and achievements. Most people with 2q37 deletion have lost the genetic material from every cell in their body. A few have only lost it in a proportion of their cells. This is called mosaicism and generally lessens the impact of the condition.

Frequent features

These features have been found to be common in a group of people with a 2q37 deletion. An individual child may or may not be affected.

• Developmental delay
• A degree of learning disability, usually mild or moderate
• Hypotonia (low muscle tone, floppiness) in babyhood and sometimes in early childhood
• Short hands and feet. The bones in the hands and feet are short, and when the hand is made into a fist, there can be a dimple where you expect to see a knuckle. The 4th and sometimes 3rd and 5th fingers are often short. This resembles a genetic condition known as Albright's hereditary osteodystrophy (AHO). Some children have unusual spacing between the fingers and toes, short arms and legs or slim, tapering fingers
• Growth delay with a tendency to put on weight by middle childhood
• Eczema
• Hernias, especially umbilical and inguinal (in the groin)
• Behavior difficulties, including autism
• Heart conditions affect one child in five

Why did this happen?
To answer this question, the parents' chromosomes need to be examined, using the same tests used to detect the arrangement in the child. (I was tested, but Victoria's Dad has never been tested) In most families, both parents have normal chromosomes. The 2q37 deletion has then happened as a once-off event and it is very unlikely that any future children will be affected. (I had two healthy pregnancies & two healthy babies after Victoria was born) Genetics call this de novo, meaning that the child with the chromosome disorder is the only person in the family known to be affected and it has not been inherited. A de novo deletion has usually occurred during the formation of the egg or the sperm. Chromosome rearrangements happen as a natural part of evolution and nothing that either parent did caused it to happen or could have prevented it. In a few families, one parent has a structural rearrangement of their own chromosomes. This is usually balanced so that all the genes and chromosome material are present and the parents are healthy. However, in these families the risk of having another affected child is higher. Your genetics service can offer you an appointment to discuss this when you are thinking about another pregnancy.

Mobility and Activity
Research reports show that most children will be delayed in reaching their developmental milestones, but they will get there in the end and some children will experience no motor delay. Low muscle tone (hypotonia, which shows as a floppiness as though the baby or child is profoundly relaxed) is extremely common but improves with maturity, practice and physiotherapy (physical therapy). Most children are mildly affected, needed physiotherapy in the preschool years only. However, some reported severe hypotonia. Those children were still under 5, but were not walking yet. Once children are on the move, balance and fatigue remain ongoing issues. On average these babies rolled at 8 months (range 3 to 14 months). They sat up at 10 months (range 4 months to 18 months), although one child only sat at the age of four and a half years. Crawling, a stage that may be by-passed in children with a chromosome disorder, was common among the studied babies who acquired the skill on average by the age of 16 months (range 10 to 26 months). Children took their first steps on average by two and a half years although there was really a wide range from 19 months to four and a half years. Some children benefited from using a stander or walker frame. (Victoria walked at 34 months) Once walking, children may lack a sense of danger and need help over uneven ground. Their gate can be unusual and they may be late in learning other mobility skills like running, hopping and skipping. When running, they may tend to hold their arms out to keep balance but even so, they fall much more often than other children and need a safe play environment and an adult hand available when out walking.

Lax Joints
Extremely lax joints can affect more than half of all children with a 2q37 deletion. Some children have hyper flexible fingers. Congenital dislocation of the hip and coxa valga (outward-turning of the hips) have also been noted, as has a particular style of tilting walk that relates to a weakness of the hip.

Spinal Curvature
Scoliosis (a sideways curve), kyphosis (a backward curve, creating a hump) and lordosis (an inward curve) may all occur.

Growth
Records show that babies grow fairly well before birth and are usually born at term, their weight ranging from 4lb 10oz to 9lb 11oz. (Victoria weighed 6lbs 8oz and they induced me right at 40 weeks)

Learning
Children are very likely to need some support with their learning, although the extent varies widely between individuals even with the same 2q37 deletion and within the same family. Many research reports suggest that delay is no more than mild to moderate. However, there is almost no detailed information. There have been some reports of severe delays.

Speech and Communication
Most children learn to talk, but speech develops late. The average age at which children spoke their first words was almost three years (range 18 months to 61/2 years). For some children there was also a reluctance to communicate, linked with autistic traits. Before learning to speak, children used gestures and vocal noises. They showed a variable degree of success with signing systems. (Victoria learned to sign key words as a baby and still remembers a lot of them today!) For some, signing unlocked the gates to communication, while others never mastered it and moved directly to speech.

Medical concerns

Most children with 2q37 deletion syndrome do not have serious medical problems. All the same, the features of the syndrome vary widely, so medical conditions can occur. The conditions are listed below in approximate order of frequency.

Kidney and Urinary Tract
Some children have a kidney anomaly or have had a urinary tract infection. One had a single kidney and another had a malpositioned kidney. Some children had a horseshoe kidney and one child had urinary reflux, a condition in which some urine returns to the kidneys rather than passing out to the bladder. Wilms' tumour is a type of kidney cancer that can occur in children with a 2q37 deletion, so a regular ultrasound scan of the renal and urinary system is usually until the age of eight.

Hernias
Inguinal hernias (part of the intestine bulges from the abdomen into a sac near the scrotum or the vagina) and umbilical hernias (part of the abdomen bulges out through the umbilical ring at the naval) are particularly common, but diaphragmatic hernias (there is a hole in the muscular sheet dividing the abdomen from the chest, allowing the contents of the abdomen to amass in the chest and take up space needed by the growing lungs) also can occur. Umbilical hernias can be minor and self heal in time. However, diaphragmatic hernias and inguinal hernias need surgical correction. (Victoria had surgery to correct her hernia at the age of 3)

Heart Conditions
All children with a known 2q37 deletion will have a careful cardiac examination as a small number have been reported to have a congenital heart condition. The range of conditions is broad - holes in the heart (atrial and ventricular septal defects), persistent ductus arteriosus and patent foramen ovale (both persisting structures of the fetal heart), coarctation (narrowing) of the aorta and a bicuspid valve (the valve that regulates blood flow from the ventricle into the aorta has only two instead of three flaps or valves). While some conditions resolve naturally with time, a few children will need surgery. Studies have shown that the children with a heart condition are now thriving either after outgrowing the condition or after surgery. (Victoria was diagnosed with the 2q37 deletion within the last five years after genetic testing. We were told to make an appointment with a cardiologist to have her heart checked and that is when they noticed three heart defects. The doctor says to have her monitored annually and surgery is a possibility later in life.
Childhood Infections
Coughs, colds and ear infections occur frequently in children with a 2q37 deletion as in other chromosome conditions. Ear and chest infections are common, attributed variously to weak chest muscles, tracheomalacia (usually floppy airways) and to aspiration pneumonia, a possible consequence of severe gastro oesophageal reflux.

Intestinal Conditions

Intestinal conditions have been found in a small number of children. Two had pyloric stenosis (the passage between the stomach and the small intestine narrows so that milk and food cannot get through), others had an obstruction of the intestines and others had their intestines were incorrectly sited within the abdomen. All of these conditions can be corrected with surgery.

Seizures

Including febtrile convulsions, seizures affected 17 to 35 percent of children in the research reports. (Victoria had "baby" (staring off & unresponsive for a few minutes) seizures when she was in Kindergarten. She was put on medication for a short period of time, but we have not noticed any signs of them since then) Evidence from imaging children's brains has shown that slightly enlarged ventricles may occur. There has also been isolated instances of hydrocephalus, excessive cerebrospinal fluid within the brain.

GenitalsMinor genitals anomalies have been found one in ten children. In boys, these have included a very small penis, small or undescended testicles. In girls the ovaries or uterus may be affected.

Hearing
Nine percent of children investigated by researchers have some degree of hearing loss. At least two children had permanent sensorineural deafness, and another had poor auditory discrimination and one child had very small ear canals, affecting hearing.

Vision

The most consistent feature was strabismus (squint or lazy eye), noted by 16 percent of  the study. One child had nystagmus and difficulty synchronising the movements of his eyes. Additionally, two children in research reports had a hooded upper eyelid, known as ptosis. Both ptosis and strabismus can be corrected with surgery. (Victoria has strabismus and has had two eye surgeries in one eye to correct it. You can still see her eye float from time to time)

Albright’s Hereditary Osteodystrophy (AHO)

AHO is a genetic condition that affects the way that calcium is laid down in the skeleton. People with AHO have subtle physical changes including short stature, a round face and a tendency to put on too much weight. Some bones in the hands
and feet are unusually short and some people have small hard lumps under the skin. They can also experience a range of hormonal problems. Most people with ‘classical’ AHO do not have a 2q37 deletion. Instead, they have low levels of a
protein (Gs-alpha) directed by a gene on chromosome 20. Up to 50 percent of people with a 2q37 deletion have unusual hands and feet, very similar to people with AHO, but they do not have any problem with their Gs-alpha gene. This shows
that other genes found at 2q37.3, perhaps glypican-1 or vigilin, must also be important for skeletal development. People with 2q37 deletion and AHO-like hands or feet usually do not have any hard lumps under the skin or the hormone problems caused by Gs-alpha deficiency.

Behaviour
Many children with 2q37 deletions do develop some kind of behavioural disorder. In the largest series of 35 people, eleven (31 percent) were known to have shown a variety of symptoms that included poor communication, repetitive behaviour,
hyperactivity, rocking and head banging, twitches, facial contortions, autism and attention deficit disorder. The high rate of behaviour disorder means that families should have access to behaviour management support.

Autism

Nine people with a 2q37 deletion and autism have been fully described and autism or repetitive, hyperactive behaviour was noted in 35 percent of children in a recent survey. Seventeen families (46 percent) said their child had autistic features. Leaving out pre-school children, the rate rose to 64 percent. Familiar types of behaviour include limited eye and social contact, repetitive behaviour such as rocking, especially under stress, exclusive focus on certain toys or objects, extreme need for predictable routines, inability to express emotional thoughts or to interact emotionally, fear of the unpredictable and, finally, distress expressed as self injury. In some children, autistic features exist alongside a social, loving and contact-loving personality. Families say repeatedly that autism undermines their child’s development more than other symptoms of the chromosome deletion. Given the frequency at which it occurs and the possible improvements from early intervention, all children with a 2q37 deletion should be screened for autism. (Victoria was tested for Autism as a baby when we first noticed some delays. Although the doctors said she did not have Autism, she still shows a lot of the behaviours that Autistic children express) Experience within studies show that the extent of the deletion is irrelevant to the development of autism. Children with deletions at 2q37.3 were just as likely to develop autism as children with a larger deletion. This observation agreed with the early evidence suggesting a possible site for an autism susceptibility gene at 2q37.3.

Might a child with 2q37 syndrome ever be able to live independently?

2q37 deletion syndrome affects children in highly variable ways. Children who are mildly affected may well be able to lead high-quality independent lives. As important as the deletion are the child's development, personality and any clinical difficulties. However, there is very limited experience. The studies oldest member is only in their twenties and currently at college learning life skills. (This has always been a question and concern for us. We are and always will be hopeful and positive through our faith that God will provide and put Victoria right where she needs to be... He's got great plans for her!)