Introduction
As early as 1953 and 1954, a group of children with IUGR (intrauterine growth retardation) were reported by Dr. Silver and Dr. Russell, respectively. They also had short stature, small triangular face, low ear, fifth finger bend, etc. The characteristic disease is therefore named Russell-Silver syndrome. Russell-Silve syndrome (referred to as RSS) is also known asSilver-Russells syndromeOr Silver syndrome. RSS is a rare congenital disease characterized by short stature and usually left and right asymmetry on both sides of the body.
Cause
The cause of the disease is not simple, the etiology is not clear, and it is basically believed to be related to heredity, but the disease-causing gene is not clear. In etiology, RSS has multiple genetic models, usually without a family history, and is generally a single case in the family. It is estimated that 7-10% of RSS patients are due to the 7th pair of maternal uniparentaldisomy, and less than 1% of RS patients have recombination at chromosome 17q25. The molecular genetic mechanisms of RSS are still unclear, and several sporadic cases suggest that it may be related to a gene (GRB10) in the 7p11.2–p12 region on the seventh pair of chromosomes (human growth factor receptor-bound protein 10). There are three main genetic models:
(1) Both seventh-pair chromosomes are derived from the mother, the so-called maternal uniparental disomy (UPD), and about 10% of cases belong to this genetic model. But the vast majority are sporadic, and almost all cases are the only cases in the family.
If it falls into this mode, the chances of family members occurring are as follows:
(a) Parents of the case: Both parents are not sick.
(b) Brothers and sisters of the case: The chances of siblings and sisters are no different from those of ordinary people.
(c) The children of the case: the probability of re-issuance of the offspring is not high.
(d) Other family members: The probability of onset is no different from that of the average person.
(2) Somatic chromosome dominant inheritance, but very rare. This model is a disease caused by mutation of two genes in a pair of chromosomes. If any one of the parents is sick, one-half of the offspring will also get sick, and one-half chance will be Give birth to normal offspring.
(3) Somatic recessive inheritance is also very rare. This model is a mutation in two genes in a pair of chromosomes. If any one of the parents has the disease-causing gene, one-half of the offspring will have the mutation, but not Will get sick, one in four can give birth to normal children, and one in four will give birth to sick children.
Cases other than this are caused by multiple reasons. When asking about family history, you must include the height and weight of the parents and brothers and sisters at birth. If no other person in the family is sick, they are all sporadic.
symptom
The disease has three clinical features: • Short stature in the uterus, asymmetrical bones on both sides, and short and inflexible little fingers.
Growth retardation results from intrauterine growth retardation (IUGR) before birth and failure to thrive after birth. Typical RSS patients will have short stature, birth weight will be 2 standard deviations below the mean, and postnatal weight and height will be 2 standard deviations lower.
Due to the asymmetry of bone development, patients may have left and right asymmetry of the head, trunk and limb bones. Among them, the limbs are the most obvious.
The patient has abnormal facial features, and the face is slightly triangular to make the forehead appear prominent, or the head of the upper half is larger because of the smaller face, and the chin is smaller. But the head circumference is in the normal range.
Other possible conditions:
In infants and young children, the bone development is immature, the front door is closed late, the blue sclera is easy to sweat, especially the head and upper body; the gastroesophageal reflux. Low muscle tone. Male infants may have cryptorchidism. The second and third feet refer to the abnormality of the spine and the lack of sacral tail bone. There will be coffee milk spots on the skin. Fasting for too long and easy to hypoglycemia (especially more obvious from 10 months to two or three years old) puberty will be early, children may have developmental delays (including exercise and cognition) and learning disabilities, but the intelligence is normal. Others: such as congenital heart disease, abnormal urinary system (kinal structural abnormalities, posterior urethral valve, hypospadias. Tumors (craniopharyngoma, seminoma, liver cancer and Wilms tumor).
diagnosis
Clinical diagnosis
Therefore, the diagnosis is based on clinical characteristics in principle: birth weight is 2 standard deviations lower than the average; body weight and height after birth are 2 standard deviations lower than the average; proportional body is short, bone age development is slow; Normal, often pseudohydrocephalus phenomenon; typical facial features such as wide forehead, small and triangular face, chin narrow and narrow; limb length imbalance; other features that are helpful for diagnosis, such as the fifth finger bend, and refers to Coffee milk spots and the length of the two arms are shorter than the height.
Other tests
There is no special laboratory test for the diagnosis of RSS, especially because the etiology of this disease is highly heterogeneous, and the following tests can be performed: cytogenetic examination - some RSS patients have recombination at chromosome 17q25. Radiation Bone Examination - To rule out bone dysplasia and cause RSS-like symptoms, X-rays can be used to check whether bone age development is slow. Molecular genetics - the genes or related genes of RSS are not known at present. The study of single-parental dimerism helps to establish the diagnosis of the 7th pair of maternal mononucleotide, and most of the RSS patients for them There are no reasons for the diagnosis.
treatment
There is no special treatment for this disease, only symptomatic treatment. Treatment focuses on height and growth, and careful observation and attention to growth rates are essential. For height, consider giving growth hormone therapy, but it can't improve the length of limbs. Childhood giving growth hormone is still not easy to reach normal height, and looks almost normal after adulthood.
For the length of the feet, you can use a rack to prevent problems. If the condition of the lower limbs and short legs exceeds 75px, treatment must be performed, otherwise it will result in compensatory (ie non-primary) scoliosis. The initial treatment can be worn with high-heeled shoes. When the age is slightly longer, the length of the lower limbs can be corrected by distraction osteogenesis or epiphysiodesis.
Fasting hypoglycemia is prone to occur between the ages of six months and three years. Therefore, if you are sick during this period, you should eat more and get enough glucose. Hypoglycemia is an important issue in the treatment. RSS children have less subcutaneous fat, usually have poor appetite and are relatively thin, so long-term treatments such as surgery will have a higher risk of producing acute hypoglycemia. .
If there is a cranial abnormality, it can be treated by a pediatric dentist during childhood or orthodontic treatment during adulthood. For some patients with severe cleft lip and palate or squatting, it is recommended that a full range of craniotomy specialists be used for treatment.
Abnormalities in the gastrointestinal part need to be actively treated, and the situation of esophagitis should be evaluated by means of sputum photography, endoscopy and pH measurement. It is recommended to prevent the feeding posture of the gastroesophageal reflux or to feed thicker foods. Avoid high-fat foods such as chocolate, coffee, cola, etc. If traditional conservative treatments are not effective, antacids (usually hydrogen ion pump inhibitors such as omeprazole or patoprazole) are needed to reduce gastric acid secretion. More severe cases must be treated with, for example, fundoplication to improve.
If there is a low tension in the baby's period, there is a possibility of stunting. At this time, the intervention of the early treatment system and physical therapy is necessary. At the same time, you must carefully observe whether there are any problems in language and listening. If there is any delay, you should quickly turn to the treatment of listening.
Because any abnormality or shortness in the body can also cause children's sensitivity to their own body image, these factors play an important role in their self-confidence, peer relationship and social skills. Therefore, proper counseling will help children grow up.
Prognosis
Although childhood is often slender, underweight, muscle weakness, developmental delay, learning disabilities, but gradually improve after puberty, can still become a healthy person, but adults are still shorter than the average person; and this disease does not cause mental retardation, There is still normal intelligence.
Genetic counseling
1. There are multiple etiology of RSS. Most patients have only one patient. The known causes include the 7th pair of chromosomes derived from maternaluniparental disomy and somatic chromosomal or somatic recessive inheritance.
2. When an RSS patient is due to the 7th pair of chromosomes derived from maternal dimorphism, it is foreseeable that the parents must not have the disease, and the risk of the patient's hand and foot will not increase, the risk of the patient's next generation may be very high. low.
3. Prenatal diagnosis is usually not feasible for RSS. However, if it is a case of maternal UPD7 belonging to the seventh pair of chromosomes, the child and the parent are treated by amniocentesis. Prenatal molecular testing is feasible. Ultrasound should be used to check if there is any growth retardation in the uterus. In general, growth and development should be clearly and carefully seen, usually waiting until the late pregnancy (about 28 weeks), thus also limiting the prenatal diagnosis.
4. For a single patient in a family, most of the pregnancy does not increase the risk of RSS.
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