Prader-Willi syndrome (PWS) is a distinct neurodevelopmental disorder associated with the deletion within the chromosomal 15q11-q13 region or uniparental disomy of chromosome 15. The etiologic heterogeneity of PWS makes it very difficult to establish uniform diagnostic methods which would result in the detection of most affected individuals. The objective was to report the clinical criteria and oro-dental features in PWS, to report the effect of diet and laser acupuncture on PWS and highlighted an easy effective method for early diagnosis of individuals with PWS. The study included seventeen cytogenetically proven individuals with Prader-Willi syndrome. These patients were subjected to meticulous history taking, clinical examination including oro-dental examination, bone densitometry and neuropsychiatric evaluation. They received laser acupuncture sessions in addition to nutrition intervention. All cases had characteristic facies, hypotonia and various psychosocial difficulties. Other criteria of PWS were present in different percentages. Karyotyping revealed deletion 15q11-q13 in 6 patients, and fluorescence in situ hybridization (FISH) revealed a microdeletion in 15q11–q13 in the other 11 patients. To our knowledge, partial ankyloglossia, median grooved tongue and hypodontia have not previously been reported in PWS patients. Laser acupuncture sessions and diet were effective in weight decline for PWS patients. Our study emphasizes the importance of early detection of PWS, laser sessions, diet restriction and oro-dental examination in the follow up of patients with Prader Willi syndrome.

Trisomy 9 mosaicism is a rare chromosome abnormality with developmental disabilities, delayed speech, facial dysmorphism and organ pathologies, the phenotype usually differs among individuals. This study presents a proband and his sib with mosaic trisomy 9 but the clinical manifestations of the boy were more severe than his sister as the number of abnormal cells were more in the boy, this could highlight the existence of phenotypic/karyotype correlation and the association of the level of mosaicism with the severity of the phenotype. This report expands the clinical manifestations of this chromosomal abnormality as multiple areas of hyperpigmentation were noticed in these cases that to the best of our knowledge have not been reported before.