title: Two novel mutations in exon 3 and 4 of low density lipoprotein (LDL) receptor gene in patients with heterozygous familial hypercholesterolemia.
abstract: OBJECTIVE
  To determine the common mutation of low density lipoprotein receptor in hypercholesterolemia patients requiring screening for heterozygous familial hypercholesterolemia (HeFH) in Karachi.
  
  
  METHODS
  Case-series.
  
  
  METHODS
  Dr. Ziauddin Hospital Laboratory and Dr. Rubina Ghani's Pathological and Molecular Laboratories, Karachi, for the PCR bench work from June 2008 to October 2009.
  
  
  METHODS
  All the patients selected for this study were from Dr. Ziauddin Hospital and National Institute of Cardiovascular Diseases. All the patients having high total cholesterol and LDL-cholesterol were included in this study with premature coronary artery diseases or a family history of hypercholesterolemia. Exclusion criteria included Diabetes mellitus, hypertension, renal disease, hypothyroidism and steroid therapy. After lipid profile with overnight fasting, DNA was extracted from whole blood collected in EDTA (ethylenediamine tetra acetic acid) tube and multiplex PCR (polymerase chain reaction) using forward and reverse primers of exons 3, 4, 9 and 14 of base pairs 162, 431, 550 and 496 respectively.
  
  
  RESULTS
  Out of total of 120 hypercholesterolemia cases, 42 patients were classical cases of HeFH (heterozygous familial hypercholesterolemia) with xanthomas, xanthelasmas and LDL-C > 160 mg/dl. The total cholesterol (260± 57 mg/dL) and LDL-C (192 ± 39 mg/dL ) of cases was significantly high as compared to, controls having total cholesterol (184 ± 27 mg/dL) and LDL-C (105 ± 22 mg/dL), p > 0.001. Two novel point mutations were noted in exon 3 and exon 4. The other 78 cases were probable with raised LDL-C (low density lipoprotein cholesterol) and family history of premature coronary heart diseases.
  
  
  CONCLUSIONS
  The frequency of HeFH was 35% classical and 65% probable cases out of total 120 hypercholesterolemia patients from two tertiary care hospitals in Karachi. The point mutation on exon 3 and exon 4 of LDLR gene was the most common. PCR is useful for the detection of large re-arrangements in the LDL-receptor gene and is a rapid and reliable method for diagnosis of familial hypercholesterolemia.
authors.affiliation: Department of Pharmacology, Ziauddin University, Karachi. samiaperwaiz@hotmail.com
authors.forename: Samia Perwaiz
authors.initials: SP
authors.lastname: Khan
authors.forename: Rubina
authors.initials: R
authors.lastname: Ghani
authors.forename: Khwaja Zafar
authors.initials: KZ
authors.lastname: Ahmed
authors.forename: Zia
authors.initials: Z
authors.lastname: Yaqoob
mesh_terms: D000368:Aged; D004247:DNA / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000097:blood / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D017354:Point Mutation; D011973:Receptors, LDL / Q000097:blood / Q000235:genetics*
chemical_list: D011973:Receptors, LDL; D004247:DNA