L1 Syndrome is a rare condition that primarily
affects the nervous system including the brain but also the nerves to the arms
and legs. The name L1 syndrome
comes from the name of the altered L1CAM
gene. Alterations in this gene affect the L1 protein which then affects nervous system development. L1
Syndrome is passed to children through the X chromosome (X- linked
recessive transmission). Because boys
only have 1 X chromosome- if they get this particular X chromosome, they will have L1 Syndrome and so it is more likely in boys. A girl has 2 X chromosomes and so would need both X
chromosomes (one from each parent) to be altered- much less likely. http://www.ncbi.nlm.nih.gov/pubmed/20301657 and http://ghr.nlm.nih.gov/condition/l1-syndrome .
Most of the abnormalities of L1 Syndrome are not
related to my field of hand and upper extremity surgery. Each child is unique but there are a series
of differences that are commonly seen.
These include hydrocephalus (too much fluid around the brain), mental retardation, delayed speech, and
spasticity. The spastic paraplegia may
require a wheelchair but also presents with a shuffling walk. Like most syndromes, the severity of any one
of these problems is different for each child.
The most common hand issue in L1 Syndrome is the
adducted thumb- it is the reason for referral to the hand surgeon. Adduction of the thumb is a position in which
the thumb is pulled towards the index (pointer) finger. The thumb can also be flexed (bent). This position of the thumb is a problem for 2 reasons. First, the thumb can be in the way
of finger motion (preventing finger flexion). Second, the thumb position simply
prevents the thumb from acting like a thumb (i.e., grabbing large objects).
In the patient below, another issue is the position of the fingers- they are deviated away from the thumb, a so- called wind- swept or wind- blown hand. This is an uncommon problem also; I most commonly see this in patients with http://ghr.nlm.nih.gov/condition/freeman-sheldon-syndrome . This combination of thumb adduction and finger position can also be a type of arthrogryposis (Distal).
Other conditions can be associated with a flexed/ adducted thumb posture including cerebral palsy (CP) and congenital clasped thumb. These conditions are each quite
different. CP may respond to splinting
and stretching but often surgery to let the thenar (thumb) muscles slide with
an EPL tendon reroutement (moving the tendon makes the tendon a abductor of the
thumb rather than an adductor) will help.
Congenital clasped thumb (present at birth) may get better with age and
splinting but also occasionally requires surgery also. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656739/
![]() |
L1 syndrome patient, left hand. Note the position of the thumb (somewhat hidden) and fingers around the wheelchair wheel. |
![]() |
The thumb in L1 syndrome. The right hand is more mildly affected here but cannot be straightened or positioned differently. |
![]() |
L1 syndrome. Left hand x-rays. The thumb is close to the fingers but the most impressive finding is the position of the fingers. They are deviated away from the thumb, a "windswept" hand. |
![]() |
Patient with L1 syndrome. Note his hand position. |
In this patient, we will plan to address the thumb with surgery (he has been splinted and in therapy for years). Hopefully, repositioning the thumb will allow improved overall function.
No comments:
Post a Comment