A diagnosis can be made when the clinical features have been identified, mainly the four common signs and symptoms. This can then be confirmed by single-gene sequencing, where the L1CAM gene is examined for any possible variations. A diagnostic test prior-to-birth is possible and very reliable when the mother is a carrier of the diseased allele. First, it's necessary to determine the fetus' sex and then study the X-chromosomes inherited from the mother. The probability of transferring the variant X-chromosome to the descendants is 50% regardless of the sex of the fetus (as illustrated by the figure). Male descendants who inherit the varied X-chromosome will express the symptoms of the syndrome, on the other hand females who inherit the varied X-chromosome will become carriers of the mutated gene and will not show any symptoms or clinical features of the syndrome.
MASA syndrome
SUNCT syndrome
TAN syndrome
SAHA syndrome
Crome syndrome
Bogart–Bacall syndrome
Njølstad syndrome
TEMPI syndrome