Ultimately, BBS is distinguished from Laurence-Moon syndrome based on which genes are affected. However, one of the genetic mutations that cause BBS has also been found in individuals with Laurence-Moon syndrome, which illustrates the difficulty in distinguishing the two. There are 14 types of BBS, each of which is caused by a different genetic mutation. These 14 genes are BBS1, BBS2, ARL6 / BBS3, BBS4, BBS5, MKKS / BBS6, BBS7, TTC8 / BBS8, B1 / BBS9, C12ORF58 / BBS10, TRIM / BBS11, C4ORF24 / FLJ35630/BBS12, FLJ20345 / MKS1, and CEP290.
An ultrasound in pregnancy can be either done as a âroutineâ ultrasound, usually between 18-20 weeks or it is done for specific reasons which usually depend at the time of pregnancy. There are essentially three different types of ultrasounds, depending on how much information is required. 1  The limited ultrasound,
How many ultrasound exams will I have during my pregnancy? You should have at least one standard exam during your pregnancy, which usually is performed at 18â22 weeks of pregnancy. Some women may have an ultrasound exam in the first trimester of pregnancy. A first-trimester ultrasound exam is not standard because it is too early to see many of the fetusâs limbs and organs in detail. An ultrasound exam done this early is used to do the following: Estimate gestational age.