The ensemble of extreme hirsutism with gingival
fibromatosis was originally described as a dominant trait. Hypertrichosis may
be present at birth but often appears at puberty. The entity was later on
defined as generalized hypertrichosis terminalis with or without gingival
hyperplasia (OMIM 135400). It has been found to be a contiguous gene syndrome
caused by microdeletions within the chromosomal region 17q24.2-q24.3.
Far in the 1857, Laurence described a bearded
and hairy female. Exhibited as a phenomenon, the young Mexican girl was
referred to as 'clothed with hairs' over her entire body except for the palms
and the soles. Hair was black and fine, and not curling. Intellect was not
reported as affected, rather the girl was reffered to as being “quick”.
We have to wait up to the 1971 for a second
report on the syndrome, when Witkop described 52 cases of gingival fibromatosis
with hypertrichosis, noting an association with epilepsy and mental
retardation.
In 2009, Sun et al. detected genomic
microdeletions of different sizes on chromosome 17q24.2-q24.3 as being the
cause of the syndrome. The minimal overlapping genomic region in the studied families
contained four genes: ABCA5, ABCA6, ABCA10, and MAP2K6. Sun et al. suggested
that MAP2K6 was the leading candidate gene from the overlapping region in their
patients.
In 2008, Blyth M et al reported
about another 2.3Mb deletion of 17q24.2-q24.3 that was associated with Carney
complex plus. The most characteristic features in this case were posterior
laryngeal cleft and the presence of numerous freckles and lentigines in
childhood. Growth restriction, microcephaly and moderate mental retardation were
also observed. The authors pointed out that the microdeletion caused haploinsufficiency
of the PRKAR1A gene.
In 2012 Lestner JM et al
reported about a girl with a 2.3 Mb de
novo deletion in chromosome 17q24.2-q24.3, whose phenotype included also skeletal
malformations (lower limb bowing, progressive scoliosis and dental
abnormalities), feeding problems, mild learning difficulties, and a
characteristic facies. They stated that the phenotype is attributable to the
deletion of KCNJ2, which causes Andersen Tawil Syndrome.
References: see text.
References: see text.
