title: Study of non-syndromic thumb aplasia in six independent cases.
abstract: OBJECTIVE
  To report on six independent and isolated cases demonstrating thumb aplasia as an essentially limb-specific phenotype.
  
  
  METHODS
  The subjects were ascertained during 2011-2013 from six different geographic regions of Pakistan, and underwent detailed clinical and phenotypic examination.
  
  
  RESULTS
  The affected arms of patients had complete absence of first digital rays, medial inclinations of second and fifth fingers, narrowing of palms, missing carpals, and shortening of zeugopod. All the subjects were presented with isolated and sporadic limb deficiencies, and five had no family history of limb or any other malformation. Parental consanguinity was denied in majority of the cases. We present detailed phenotypic manifestation of thumb apalsia in these subjects.
  
  
  CONCLUSIONS
  Thumb aplasia markedly impairs the normal function of affected hand. Surgical procedures like pollicisation of the index finger should be employed to improve the quality of life of these subjects. There is so far no specific genetic factor known for isolated thumb aplasia, compromising an accurate genetic counseling. Collection of patients with similar phenotypic presentations could be useful in further molecular genetic investigations.
authors.affiliation: Hafiza Fizzah Riaz, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Hafiza Fizzah
authors.initials: HF
authors.lastname: Riaz
authors.affiliation: Karmoon Lal, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Karmoon
authors.initials: K
authors.lastname: Lal
authors.affiliation: Bashir Ahmad, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Bashir
authors.initials: B
authors.lastname: Ahmad
authors.affiliation: Muhammad Shuaib, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shuaib
authors.affiliation: Syeda Farwa Naqvi, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Syeda Farwa
authors.initials: SF
authors.lastname: Naqvi
authors.affiliation: Sajid Malik, Human Genetics Program, Department of Animal Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
authors.forename: Sajid
authors.initials: S
authors.lastname: Malik
keywords: Absence deformity; Absent digit; Limb anomaly; Limb defects; Oligodactyly; Pakistani subjects; Thumb aplasia