What type of mutation causes mental retardation?

What type of mutation causes mental retardation?

Specific examples of metabolic disorders with prominent MRDD include phenylketonuria, maternal phenylketonuria, Lesch-Nyhan, galactosemia, and adrenoleukodystrophy. o Down Syndrome is the leading genetic cause of mental retardation, occurring in about 1/800-1000 births.

Which is the most common chromosomal abnormality that leads to mental retardation?

Down syndrome is the most frequent genetic cause of mental retardation.

Is chromosome deletion a disability?

Chromosomal deletion syndromes result from loss of parts of chromosomes. They may cause severe congenital anomalies and significant intellectual and physical disability.

How common is 13q deletion syndrome?

Epidemiology. It is incredibly rare, with fewer than 190 cases described. Although rare, deletions involving chromosome 13q are among the most commonly observed monosomies Chromosome 13, Partial Monosomy 13q appears to affect females slightly more frequently than males.

Can a mentally challenged person have a normal child?

Retarded women who do get pregnant, though, usually deliver normal babies, says Andrew Tymchuk of the UCLA medical school’s psychiatry department, who notes that people with severe genetic problems tend to be infertile and most mild kinds of retardation typically are not passed on.

What are the biological causes for mental retardation?

Biological risk factors for mental retardation include malnutrition; exposure to toxins such as lead, alcohol, and PCBs, and being born at LBW. Social in¯ uences from homes, schools, and cultures are related to intelligence and mental retardation although the direction of effect is difficult to determine.

What are the chromosomal abnormalities in Down syndrome?

Typically, a baby is born with 46 chromosomes. Babies with Down syndrome have an extra copy of one of these chromosomes, chromosome 21. A medical term for having an extra copy of a chromosome is ‘trisomy. ‘ Down syndrome is also referred to as Trisomy 21.

What is severe mental retardation?

Severe mental retardation is defined by a tested IQ of between 20 to 25 and 35 to 40. ○ Profound mental retardation is defined by a tested IQ of less than 20 to 25. • Approximately 70% of cases of severe to profound mental retardation have a known cause.

What are the characteristics of chromosome 13q14 deletion syndrome?

▼ Description. The chromosome 13q14 deletion syndrome is characterized by retinoblastoma ( 180200 ), variable degrees of mental impairment, and characteristic facial features, including high forehead, prominent philtrum, and anteverted earlobes (summary by Caselli et al., 2007 ).

Are there any heart defects associated with monosomy 13q?

In some cases, heart malformations may be associated with Partial Monosomy 13q including Atrial and Ventricular Septal Defects, which are rare heart defects that are present at birth (congenital). The normal heart has four chambers with two upper chambers known as atria.

What is the treatment for partial monosomy 13q?

Other treatment of Chromosome 13, Partial Monosomy 13q is symptomatic and supportive. A team approach may be helpful in ensuring that affected individuals reach their fullest potential. Such a team approach may include special remedial education, physical therapy, and other medical, social, or vocational services.

What is the degree of intellectual disability on chromosome 13?

However, in some affected individuals, the degree of intellectual disability may be mild or moderate.