El Darouti et al, 1988, reported three patients with Papillon-Lefevre syndrome who showed a remarkable degree of improvement after treatment with an oral retinoid.

Ghaffer et al, 1999, studied 15 patients with Pappilon-Lefevre syndrome from 4 affected families and concluded that specific neutrophil dysfunction appeared to be etiologically involved in the disorder.

Hattab et al, 1995, described the clinical, laboratory and radiological features of 4 PLS patients belonging to two consanguineous Jordanian families. 

Abou Chedid et al. (2019) described a 5-year old boy who presented with spontaneous loss of all primary teeth, and palmoplantar hyperkeratosis. He belonged to a multiply consanguineous family, and had two other similarly affected cousins. 

Pareek and Al-Aska, 1986, reported the clinical symptoms of six Saudi siblings with Papillon-Lefevre syndrome. The patients belonged to a consanguineous family from a village near Riyadh where the authors had noticed at least 10 more cases of Papillon Lefèvre syndrome.

Kellum, 1998, described a consanguineous Saudi family, in which four siblings were diagnosed with Lefèvre syndrome. The patients were found to show remarkable improvement in hyperkeratosis following treatment with etretinate. 

Almuneef et al, 2003, described a Saudi male, born to consanguineous parents, with pyogenic liver abscesses and PLS.  They found several other reports of this association and concluded that liver abscess is an important complication of neutrophil dysfunction in Papillon-Lefevre syndrome.

Ghandour, 1989, reported two Sudanese children with hyperkeratosis palmoplantaris or Papillon-Lefevre syndrome (PLS).