Russell Silver Syndrome
Russell-Silver syndrome (RSS) is one of the recognized forms of intrauterine growth retardation (IUGR) diseases. It was first independently described by H. K. Silver in 1953 and by A. Russell in 1954.
Russell Silver Syndrome is very rare occurring in approximately 1/75000 births. Little is known about the cause of this condition, in the majority of families only one child is affected but very occasionally families do have more than one affected child. This may suggest a genetic basis for this condition and this is the subject of much research.
Diagnosis
A low birth weight is defined as a baby born with a weight that is inappropriately low for the duration of the pregnancy - for a baby born at term this would be a birth weight less than 2.5kg. The inappropriately low weight indicates that the growth of the baby in the womb has been unsatisfactory and this is why is is called Intrauterine Growth Retardation.
The majority of babies born small for their gestational age show catch-up growth over the first two or three years of life. However, in about a third complete catch-up growth does not occur. These children remain small and fail to reach their genetic potential as defined by their parental heights.
The diagnosis of Russell Silver syndrome is similar to IUGR and is based on comparison of the babies weight centile at birth with standards which take into account the gestational age of the baby, ideally infant length should also be taken into account.
Symptoms
Feeding problems - early feeding problems are common. The baby is often disinterested in feeding and takes only small amounts with difficulty
Sweating - the babies sweat a lot, especially at night, and have a greyness or pallor of the skin. In some infants, this is a symptom of a low level of sugar in the blood (hypoglycaemia). As they get older, these infants/children may have altered behaviour, such as hyperactivity or, conversely, tiredness, as a symptom of their low blood sugar level
Face - the face is triangular shaped with a small jaw and a pointed chin. The mouth tends to curve down
Eyes - a blue tinge to the whites of the eyes in younger children
Head - the head circumference may be of normal size, which means it can appear large in comparison to a small body size
Fontanelle - the opening between the bones of the skull, the fontanella, may be very wide and late to close in babies
Clinodactaly - the little finger on each hand may be small and curve inwards
Body asymmetry - one side of the body grows more slowly than the other
Continued poor growth - with no "catch up" into the normal centile lines on the growth chart
Puberty - may commence at an early age
Overview
The term IUGR probably represents a spectrum of conditions (some of which are described as Russell Silver syndrome) resulting from abnormal foetal growth. As with any syndrome, not every child will have all the features described. The child who has IUGR, but has not experiences 'catch-up' growth during the first year of life, will remain small for their age and probably very thin. Their final height may be in the region of 157cm (5'2") for a boy and 144cm (4'9") for a girl.
There are many features of IUGR which may require medical help and support and it is important that you discuss any concerns that you have with your growth specialist who can then refer your child to another appropriate specialist if necessary. This may be especially relevant when considering leg asymmetry and the referral to an orthopaedic surgeon with experience in the procedure of limb lengthening (and not shortening).
There is no definitive way to help with achieving weight gain although it often causes much concern. These children are healthy and active, and confrontation over food should be avoided if possible. There is no treatment at present that can be of certain long-term benefit for growth. The use of growth hormone appears to improve the rate of growth in the first five years of treatment, but longer-term benefit is as yet uncertain and clinical studies are still ongoing. The estimates of adult height after growth hormone treatment will not be known until these studies are complete.
Acknowledgements
The information above has been kindly obtained with permission from the Child Growth Foundation and is summarised from the booklet "Intrauterine Growth Retardation (IUGR) including Russell Silver Syndrome - A Guide for parents and patients" available from the CGF.