An insight into genetics of non-syndromic cleft palate
Proband is a 29-year-old man who is affected with CP and was under treatment at Cleft Lip and Palate Clinic of Isfahan Medical University. Based on the medical interview, physical exams, echocardiogram, ophthalmologic evaluations, eudiometry test, and a routine blood examination, especially for checking if thyroid and parathyroid hormones were normal, the patient was diagnosed to have non-syndromic soft CP with hypernasality. He was born in a third-degree consanguineous marriage and was originally from Charmahal-Bakhtiyari province of Iran. He had a third-degree consanguineous marriage and has a 3-year-old healthy daughter, but his uncle IV-8 and nephew (VI-4) were affected by soft CP. Study of about six generations of this family pedigree showed that CP repeatedly occurred in males []. Another considerable point in this pedigree is that the sister of the proband (V-3) who has been affected with hypernasality disorder has an affected son. Regarding the occurrence of the disorder only in males who were born in consanguineous and non-consanguineous marriages in several successive generations, It seems that CP is a genetic disease in this family and its inheritance pattern is X-linked recessive.It seems that the sister of proband (V-3) is carrier of soft CP, leading to an affected son. Howevere, regarding the X-linked recessive inheritance pattern of the disorder, V-3 should not be affected phenotypically, like the other carrier females of the pedigree who have affected sons. But V-3 showed the mild form of disorder by just having hypernasality that is probably due to unusual inactivation of the X-chromosome, so that mutated copy of the gene is located on the X chromosome which is active in most of the cells.